• ISSN 1000-0615
  • CN 31-1283/S
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Effect of KK-42 on the carapace ultrastructure in Macrobrachium nipponense during postmolt
Junfang ZHANG, Juan DU, Ke CHEN, Hong YANG, Qianji NING
Accepted Manuscript  doi: 10.11964/jfc.20190311677
[Abstract](0) [FullText HTML](0) [PDF 820KB](0)
Abstract:
The previous studies found that KK-42 treatment can significantly shorten the duration of molting cycle in juvenile prawn Macrobrachium nipponense, and increase the thickness of the carapace endocuticle in late premolt (D3 stage). In order to further investigate the effect of KK-42 on cuticle structure, the juvenile prawns in postmolt stage during which the formation of exocuticle gradually ends but that of endocuticle starts, were employed to study the structures of carapace exocuticle and endocuticle using the observation of paraffin section by scanning electron microscopy (SEM). Healthy intermolt juvenile prawns with body length of 3.5±0.1 cm were randomly divided into two groups. The prawns were soaked for 1 min in KK-42 solution at a concentration of 1.95×10-4 mol/L (treatment group) or 0 mol /L (control group), respectively. The carapaces of juvenile prawns at 1.5, 3, 6 and 12 h after molting were obtained to be used for ultrastructural observation. To observe directly the surface structure of endocuticle, the carapace obtained at 6 h after molting was scraped gently with an anatomical knife to remove tissues on the inner surface of carapace, and then examined using SEM. The results showed that the carapace was only composed of the epicuticle and exocuticle at 1.5 and 3 h after molting. The number of exocuticle lamellae derived from KK-42 treatment group rised significantly at 1.5 and 3 h after molting, and the thickness of exocuticle increased by 72.07% and 38.67%, respectively, compared with the corresponding control group. At 6 and 12 h after molting, the loose lamellaes in exocuticle tended to be dense, and there was no significant difference in thickness to be found between two groups. The number of endocuticle lamellar with a loose structure, being only one at 6 h, separately increased to two in control group and three in treatment group at 12 h after molting. In addition, pore canals within the endocuticle presented different sizes and head-tail orientation. No significant structural change was observed in the endocuticle after KK-42 treatment. The results reveal that KK-42 treatment has a significant effect on the carapace ultrastructure of juvenile M. nipponense during postmolt, and accelerate the formation rate of the exocuticle as well as endocuticle.
Primary Cell Culture and Identification of brain neurons in Chinese perch (Siniperca chuatsi)
LinJie SHI, Xufang LIANG, Shan HE, Jian PENG
Accepted Manuscript  doi: 10.11964/jfc.20190111630
[Abstract](0) [FullText HTML](0) [PDF 734KB](0)
Abstract:
The diversity of species makes the research on cell level of Chinese perch extremely limited. Establishing a simple and feasible method for primary culture of brain neurons from Chinese perch (Siniperca chuatsi) in vitro is beneficial to further study on fish nervous system. Our laboratory combined with the usual method of cell culture, Chinese perch brain neruons (born 3 months) were isolated by collagenase digestion and mechanical blow. L15+20%FBS suspended brain neruons were inoculated on the cell culture vessels, in 28 °C without CO2 incubator. The medium was replaced after 3 days. Subculture was carried out after the cells covered with the bottom of the cell culture vessels. The morphological changes of the neurons were observed under inverted phase-contrast microscope; Immunofluorescence staining for NeuN or β-tubulin was performed to identify the purity of neurons. The results showed that the cells began to adhere to the culture bottle and develop small neurites and form network gradually after Primary culture for 2 days. Up to the 5th day, many neurites extended to form dense network and Soma of neurons became well. Fluorescence staining with NeuN or β-tubulin showed that the purity of neurons can reach above 95%. The present protocol is a simple and efficient method for culturing brain neurons of Chinese perch with high purity, Which is of great significance for the fine study of fish growth and development, expression regulation of various receptors and proteins, cell apoptosis and cell signal transduction.
Bioinformatics analysis of regulatory non-coding RNA in gonad of Crassostrea gigas
Xue WANG, Weijun WANG, Qihao LUO, Guohua SUN, Yanwei FENG, Jingjun MA, Jianmin YANG
Accepted Manuscript  doi: 10.11964/jfc.20190211659
[Abstract](0) [FullText HTML](0) [PDF 1074KB](0)
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A plenty of non-coding RNAs (ncRNAs) have been identified through the application of high-throughput analysis of the transcriptome, and this has led to an intensive search for possible biological functions attributable to these transcripts. In this study, the gonad tissue of the two-year-age Crassostrea gigas of same family cultured in Rizhao Huanghai area were used to identify a large number of miRNA, lncRNA and circRNA by small RNA-seq and RNA-seq, and their biological characteristics were analyzed. The results showed that, with Danio rerio as a reference, 25-30 known miRNA matures and 51-63 known miRNA hairpin was obtained, 53-71 new miRNA matures and 53-77 new miRNA hairpin were predicted. The length of miRNA in C. gigas ranged from 18-26 nt, where the largest number was in the 20-22 nt and the first nucleotide position was tent to U. 2302-2349 known lncRNA transcripts were obtained, and 20083-24114 new lncRNA were predicted. Among them, the percentage of the intergenic lncRNA, intronic lncRNA and antisense lncRNA was 29.0%, 62.1%, and 8.9%, respectively. The data showed that genomic characteristics of lncRNA in C. gigas were similar to those of other eukaryotes. Compared with mRNA, the transcript and open reading frame of lncRNA was much shorter at length and much lower at expression level. 383 circRNA transcripts were obtained, among which the average percentage of 88.54% came from exon, 4.51% came from intronic and 6.95% came from intergenic. The data showed that the endogenous circRNA have a lot miRNA target sites. This study showed that the basic biological characteristics of miRNA, lncRNA and circRNA in C. gigas. The results set the foundation for the subsequent research on the expression and biological function of regulatory non-coding RNA in C. gigas.
Identification and characterization of the calcineurin B in Fenneropenaeus chinensis: its implications on competitive ability
Li SUN, Xia LU, Jie KONG, Xianhong MENG, Yunjun YAN, Bobo LI, Weipeng ZHONG, Baolong CHEN, Baoxiang CAO, Kun LUO, Sheng LUAN
Accepted Manuscript  doi: 10.11964/jfc.20190111623
[Abstract](49) [FullText HTML](26) [PDF 1175KB](2)
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Competitive behavior exists widely in animal and plant groups. When groups or individuals have the same needs for the limited resources, competition will occur in intra-species or inter-species. The existence of competitive behavior can significantly affect the growth performance of individuals. There is strong competitive behavior in the breeding of Fenneropenaeus chinensis, and we has proved that the competitive behavior among individuals of F. chinensis has a significant effect on individual growth traits, and this effect can be inherited. However, little information was available for the molecular mechanism of competition behavior in shrimp. Candidate genes involved in competitive behavior of F. chinensis have been identified by comparative transcriptome analysis in our previous study, among which there is a calcineurin (CN) B gene. CN is a highly conserved Ca2+/calmodulin (CaM)-dependent serine/threonine phosphatase, which composes of a catalytic subunit (CNA) and a regulatory subunit (CNB). Previous studies reported that CN-B played an important role in the central nervous system mediated by Ca2+/CaM. In order to further prove the role of CN-B gene in the competitive behavior, in the present study, the full-length cDNA of CN-B of F. chinensis (FcCN-B) was cloned by RACE technology, and its expression in different tissues (nervous, heart, stomach, hepatopancreas, and intestine) between high competitive group (HCG) and low competitive group (LCG) was analyzed by Real-time PCR. The results show that the full-length cDNA of FcCN-B is 2867 bp, containing 95 bp of 5′ untranslated regions (UTR), 540 bp of open reading frame (ORF), and 2232 bp of 3′ UTR. There are four conserved EF-hand Ca2+ binding domains in the ORF of FcCN-B. Protein homology analysis indicated that the amino acid sequence of FcCN-B has high homology with other species (78.8%-93.8%), among which FcCN-B has the highest homology with Eriocheir sinensis (93.8%) and then with Drosophila. melanogaster (90.5%). The phylogenetic relationship analysis showed that vertebrates and invertebrates were independently clustered into two branches. Furthermore, F. chinensis was clustered with E. sinensis into an independent branches, and then it was clustered to D. melanogaster, which suggesting that FcCN-B might have similar functions as it did in D. melanogaster. The results of Real-time PCR showed that the expression of FcCN-B in the nerve ganglion was significantly higher in HCG than in LCG, but its expression in heat was significantly lower in HCG than in LCG. This study preliminarily proved that the calcineurin B may play a certain role in the competition behavior of F. chinensis, and will lay an important foundation for investigating the molecular mechanism of the competition behavior of F. chinensis.
The body condition and reproductive investment of Dosidicus gigas in the equatorial waters of eastern Pacific Ocean
Fei HAN, Xinjun CHEN, Dongming LIN, Sipeng XUAN
Accepted Manuscript  doi: 10.11964/jfc.20180611323
[Abstract](33) [FullText HTML](20) [PDF 1394KB](1)
Abstract:
Extant cephalopod species are characterized by the lag of sexual maturation, when compared to their body growth. And they have evolved a range of flexible reproductive strategies, that are associated with different characteristics of body growth and reproductive investment, and the latter is vital important to understand their reproduction. In this study, the specimens of Dosidicus gigas, collected from equatorial waters of eastern Pacific Ocean during a jigging fishery period from February to April 2017, were used to explore their body condition and reproductive investment, by applying morphology and residual index analysis methods. Both female and male individuals were found isometric growth, according to weight-length relationship analysis. Female D. gigas attained maturation from mantle length (ML) of 270 mm and body weight (BW) of 766 g; whereas, males were found maturity from 270 mm ML and 479 g BW. Both female and male individuals had the lowest rate of zero stomach fullness degree (FD), with the majority being found at FD of 1-2. Along with the sampled months, D. gigas showed a better body condition, but which was the worst during the sexual maturation period. The gonadosomatic index (GSI) was measured a mean value of 2.26%±1.33% for sexual mature females, and nidamental index was estimated 34.34%±18.62%. Mature males had a mean GSI of 1.31%±0.35%. The body condition indices, measured as the standardized residuals of body weight and mantle length relationship, and reproductive investment indices, measured as the standardized residuals of reproductive system weight and mantle length relationship, showed a decreasing trend with sexual maturation. When corresponding to stomach fullness degree, the body condition index showed a decreasing trend, whereas the reproductive investment index increased with higher stomach fullness degree. However, there was a significantly positive relationship between indices of body condition and reproductive investment. Therefore, these evidences indicated that D. gigas continue feeding during sexual maturation, and the energy sourcing for reproduction is mostly from food intake. Meanwhile, energy reserve in the muscle tissues might be mobilized to meet the high energy demand during gonadal development.
Experimental study and analysis of local scouring of artificial reef on silty sand bed under steady currents
Ling DING, Jiamei WANG, Zhenzhao TANG, Haigang CHEN, Xiaoping JIA
In Press  doi: 10.11964/jfc.20190511816
[Abstract](467) [FullText HTML](309) [PDF 1379KB](2)
Abstract:
Artificial reefs (ARs) are an important part of marine ranching, which are installed in seabed to protect and cultivate marine life systems. After ARs are deployed, changes in seabed conditions may intensify local scouring of seabed nearby ARs and influence the stability of ARs. Therefore, it is necessary to investigate the scouring characteristics. In this study, a physical model experiment was conducted in an experimental sink to investigate the local scouring of an artificial reef at different water flow velocities, which was placed on silty sand bed. The experiment results show that the scouring response of the silty bed to the 0.11 m/s flow velocity is not significant. The depth of the scouring hole behind the reef model is 0.5 mm, and there is no obvious scouring hole on both sides. When the flow velocity increases to 0.22 and 0.27 m/s, sand scales are uniformly distributed on the surface of sand bed. The depth of the scouring hole behind is 1.0 and 1.5 mm respectively. The maximum depth of the scouring holes on both sides is 4.5 mm and the width is 4.0 cm and 7.5 cm respectively. Combined with the experiment results, the numerical simulation method was introduced to analyse the mechanism of scouring phenomenon nearby ARs. According to the simulation, the flow field, shear force and vortex distribution are similar to the scouring pattern of silty sand bed in the experiments. The numerical simulation results show that the holes in the surface and multi-legs of reef increase the flow and scouring strength. The high value area of above three parameters corresponds to the area with stronger scouring. It is concluded that the scouring strength of ARs in the silty sand bed increases with flow velocity, but it is not strong enough to influence the stability of reef model. The structure of ARs does have effects on the local scouring. Flow field, stability and scouring pattern should be taken into consideration during the design of ARs.
Marine ranching and fishery stock enhancement in the Xiangshan Bay
Yunlong WANG, Shengfa LI, Yazhou JIANG, Shouyu ZHANG, Qingsong HU, Jikang SHENTU, Haifeng JIAO
In Press  doi: 10.11964/jfc.20190611845
[Abstract](79) [FullText HTML](51) [PDF 957KB](3)
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In order to establish a marine ranching demonstration area in the Xiangshan Bay for an effective restoration of biological resources and maximum output of fisheries resources in natural waters, habitat for biological resources was built, suitable proliferation species were screened and applied, ranchable species were multiplied and harvested, and a series of assessment and management techniques were applied. Seven groups of reefs consisting of 15 hexagons and 1 000 roundtable frame-type induction reefs were constructed with an area of 25 hm2 and space of 53 810 m3. Large algae such as Laminaria japonica, Porphyra haitanensis and Gracilariopsis lemaneiformis were transplanted. Artificial ranch of 80 hm2 for algae, floating plane algae beds as majority and three-dimensional floating algae beds as assistance, were built. Twenty million shellfish including Scapharca subcrenata and Atrina pectinata were cultured by bottom sowing; 1.6 million fish such as Pseudosciaena crocea, Sparus macrocephlus, Nibea albiflora and Sebastiscus marmoratus were released annually; and ten million shrimps such as Fenneropenaeus chinensis, Marsupenaeus japonicas were released annually. Survey results show that the degree of eutrophication in ranch demonstration area has decreased, primary and secondary productivity improved significantly, with algae biomass 18 000 kg/hm2. Fishery resources exhibited positive response to the marine ranching. Nineteen months after reef deployment, species richness, the total biomass and abundance of demersal nekton assemblage in the impact area were 1.32, 2.04 and 1.49 times higher, respectively, than those in the control areas.
Research on landscape structure and pattern of marine ranching in Zhelin Bay, East Guangdong
Dingyu DUAN, Chuanxin QIN, Wentao ZHU, Hongmei MA
In Press  doi: 10.11964/jfc.20190511805
[Abstract](819) [FullText HTML](482) [PDF 824KB](10)
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The integrated development of marine ranching and recreational fishery is one of the development directions of marine ranching in China. At the present stage, the marine ranching leisure industry is small in scale and single in type, mainly for recreational fishing and diving, and its landscape ornamental function needs to be further explored and developed. The research on the landscape pattern of marine ranching mainly focuses on the formation and distribution of marine ranching landscape resources as well as their layout and arrangement in landscape space, aiming to understand the specific embodiment of the variation degree of its ecosystem or spatial attributes. Taking the marine ranching demonstration area in Zhelin Bay in eastern Guangdong Province as the research case, this paper used landscape pattern analysis method to calculate the characteristic index of landscape elements and the heterogeneity index of landscape. The results showed that the natural landscape in the marine ranching demonstration area in Zhelin Bay in eastern Guangdong Province is the landscape matrix, however, because of the largest patch area in the semi-natural landscape and the the highest fragmentation index, it is most affected by human activities, therefore the protection of biodiversity and the maintenance of landscape habitat should be strengthened. In addition, the large degree of separation between cultural landscape and the overall landscape leads to the poor connectivity of the overall landscape, affecting the landscape effect; The coastal landscape patches are few and the richness is not high, however, according to the survey, the surrounding tourism resources are abundant, so there is a lack of integrated development and utilization with marine ranching in Zhelin Bay, eastern Guangdong Province. In short, by analyzing the distribution and interaction of different landscapes in the pattern space of marine ranching landscape, this paper can provide data support for the next step of landscape ecological planning, and provide support for the development and utilization of marine ranching recreational fisheries and ecological landscape sustainable development, comprehensively enhancing the ecological, economic and social values of marine ranching.
Strategy optimization of stock enhancement of golden cuttlefish, Sepia esculenta based on structural characteristics of reproductive and recruitment population
Xiumei ZHANG, Linlong WANG, Yuyang ZHANG, Gang LUO, Haoyuan GAO
In Press  doi: 10.11964/jfc.20190711877
[Abstract](818) [FullText HTML](447) [PDF 1321KB](16)
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Golden cuttlefish, Sepia esculenta, was one of the largest economic cephalopods in Chinese northern seas, with an annual yield of more than 1 000 tons until the 1970 s. Since then, with the continuous expansion of fishing activities and dwindling of spawning field, this species has greatly reduced its local abundance compared with the previous condition due to its biological sensitivity to the environment (one-year life cycle and low fecundity). For this situation, many measures have been adopted to boost the population to meet the needs of human consumption, such as the release of artificially hatched juveniles and restoration of spawning habitats. The primary objective of this study is to optimize the existing conservation strategies and methods of cuttlefish by exploring the structural characteristics of the cuttlefish population in Qingdao coastal waters. The brood amount and size of egg cells of adult cuttlefish in 2017 were calculated. The distribution of body length and spatiotemporal migration process of juveniles were analyzed by using continuous monitoring methods. Results showed a decreasing trend in the specification of golden cuttlefish that arrived at different stages during the grouping period (May- July). The brood amount and size of egg cells of breeding cuttlefish in the early-stage were significantly higher than those of middle- and later-stages. The fertilized eggs of cuttlefish are characterized by sinking and stickiness, thus attaching to the attachment, such as algae or reefs. For juvenile cuttlefish, they grow rapidly, and the dispersion level of body specifications increases with sampling time due to the long grouping period and spawning in batches habits of breeding cuttlefish. This behavior might be a reproductive strategy for avoiding intraspecific feeding competition and promoting the differentiation of spatial niche. Therefore, according to the actual brood amount and the quality of eggs in the collection periods of breeding cuttlefish, it is suggested that the utilization ratio of the early-stage population should be increased to improve breeding efficiency and guarantee the supply of large-size juveniles. The placement of spawning substrates in the spawning ground (slow-flowing area, 15-20 m) of adult cuttlefish from May to July is an important measure of resource restoration. Based on the reproductive habits of breeding cuttlefish, background survey in food abundance of release’s water for juvenile cuttlefish is indispensable. To reduce the intraspecific predation pressure and improve the survival rate of released population during large-scale juveniles’ release, juveniles’ release in different periods should be taken into consideration. In order to further optimize the mode of resource restoration and reduce the cost of the proliferation of cuttlefish, we also suggest exploring the technology of releasing fertilized eggs.
Growth, mortality and reasonable utilization of Sebastes schlegelii in the artificial reef area of Weihai, Shandong Province
Mengmeng ZHANG, Yue LIU, Tao XIE, Wenlei CHEN, Yanli TANG
In Press  doi: 10.11964/jfc.20190411742
[Abstract](657) [FullText HTML](425) [PDF 1520KB](4)
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The artificial reefs are an important part of the marine ranching. Sebastes schlegelii which occurs in the coastal waters of China, including Yellow Sea and East China Sea, is a delicious seafood and has great economic value. We studied the resource status of S. schlegelii in different reef areas, such as growth, mortality and utilization of resources assessment, based on the cage questionnaire data in Weihai artificial reef area, Shandong province, from 2016 to 2018, by the means of ELEFAN Ⅰ, length-converted catch curve, Yw/R curve and the biologic reference points. And uncertainty was incorporated into the estimation of the biological reference points F0.1 and Fmax by Monte Carlo simulation. The results of the first study on the resources of reef areas at different depths showed that the average body length, average weight, asymptotic body length and asymptotic weight of the S. schlegelii in shallow water areas were greater than those in the middle waters, and the deep water areas were the smallest, indicating that the artificial reefs in shallow water areas were more conducive to the protection of fishery resources. The fishing mortality coefficient and the natural mortality coefficient in the middle water area were greater than the deep water area, the shallow water area was the smallest. It is the first time to apply biological reference points F0.1, Fmax and uncertainty analysis to the resource assessment of different depths of reef area. The result showed that the judgment results of FBRP at the three uncertainty levels were consistent with the none uncertainty, but the value of Fmax was far greater than F0.1, making it more difficult to judge the amount of reef resources as overexploitation. Therefore F0.1 is more suitable for the evaluation of S. schlegelii. In combination with Gulland’s theory, biological reference points and yield per recruitment, reef resources were under the mild exploitation, and fishing intensity can be appropriately enhanced to increase catch yield. Shallow waters can be increased to F=0.39, and Yw/R=25.60, corresponding fishing age is 1.83 a. The middle water area can be increased to F=0.46,Yw/R=23.89 and fishing age 0.93 a, respectively. Deep water area can be increased to F=0.42, and Yw/R=16.74 corresponding to a fishing age of 1.12 a.
Effects of dietary sodium selenite and selenoyeast on growth performance, Se accumulation, antioxidant responses and low temperature stress resistance of juvenile yellow catfish (Pelteobagrus fulvidraco)
Junru HU, Guoxia WANG, Yuping SUN, Hongxia ZHAO, Yanhua HUANG, Junming CAO
In Press  doi: 10.11964/jfc.20181011479
[Abstract](1307) [FullText HTML](696) [PDF 721KB](7)
Abstract:
In order to investigate the effects of dietary sodium selenite and selenoyeast on growth performance, Se accumulation, antioxidant responses and low temperature stress resistance of juvenile yellow catfish Pelteobagrus fulvidraco, four isonitrogenous and isolipid diets containing graded levels of Se, 0.028 (control, G0), 0.25 (sodium selenite, G1), 0.30 (selenoyeast, G2), 0.52 (selenoyeast, G3) mg/kg were randomly fed to yellow catfish [initial weight (2.12±0.01) g] for 56 days. At the end of breeding experiment, the low temperature stress was conducted. The results showed that sodium selenite and selenoyeast had no significant effects on the final weight, weight gain rate, feed coefficient and survival rate. Sodium selenite and selenium yeast significantly increased the selenium content of whole body and muscle, G3 group was significantly higher. The selenium content of whole body was no significant difference between G1 and G2 groups, but the selenium content of muscle in G2 group was significantly higher than that of G1 group. Sodium selenite and selenium yeast significantly increased GPx activity in liver. In G1 and G2 groups, SOD activity was significantly higher than that in G0 group. At 22 °C, the total protein, cholesterol, triglycerides, and urea nitrogen content were no significant difference among all the groups, but G2 group had a significantly higher glucose than G0 and G1 groups. The relative expression of HSP70mRNA was not significant difference. At 13 °C, the total protein, cholesterol content were no significant difference. The triglyceride content in G1 group was significantly higher than that in G0 and G3 group, but was not significantly different compared to G2 group. Glucose in G2 and G3 groups were significantly higher than that in G0 and G1 groups. The urea nitrogen content in G2 group was significantly lower than that in G1 group. The relative expression of HSP70 mRNA in G0 group was significantly higher than that in other groups. The results showed that 0.30 mg/kg selenoyeast in juvenile yellow catfish diet was better than 0.25 mg/kg sodium selenite, taken the growth performance, selenium deposition, antioxidant activity and low temperature stress resistance as considered.
Effects of dietary baicalein on growth, serum anti-oxidation indicators and flesh quality of Ctenopharyngodon idella
Zhen XU, Hang YANG, Gaoyang LIANG, Bowei GAO, Xiaoqin LI, Xiangjun LENG
In Press  doi: 10.11964/jfc.20181011485
[Abstract](1202) [FullText HTML](637) [PDF 847KB](17)
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To investigate the effects of dietary baicalein on the growth performance, anti-oxidation indicators and flesh quality of grass carp, five diets were prepared with the baicalein inclusion at 0 (control diet), 0.1, 0.2, 0.4, 0.6 g/kg, and fed to grass carp with an initial body weight of (75.8±0.24) g. After 60 days of feeding, the weight gain showed quadratic relationship with dietary baicalein level, and the supplementation of 0.2 g/kg baicalein improved weight gain by 8.63% and decreased feed conversion ratio by 0.14 when compared to the control group. Serum SOD activity were increased and MDA level were decreased by the addition of 0.2~0.6 g/kg baicalein. Serum CAT activity were also increased by the addition of 0.4 g/kg baicalein, while AKP and lysozyme activity showed no significant difference among groups. The inclusion of 0.4 and 0.6 g/kg baicalein increased the total amino acids and the total essential amino acids in flesh, and the total nonessential amino acids were increased by the addition of 0.6 g/kg baicalein. There were no significant difference in the proximate composition and water-holding capacity of flesh, and muscle fiber density and diameter also showed no difference among groups. In conclusion, dietary baicalein could improve the growth and anti-oxidant ability of grass carp, and the recommended supplemental level of baicalein was 0.2 g/kg.
Difference of individual size on beak morphology of Sthenoteuthis oualaniensis in the Xisha Islands of South China Sea
Ziyue Chen, Huajie LU, Yuhe Tong, Wei Liu, Xu Zhang, Xinjun CHEN
Accepted Manuscript  doi: 10.11964/jfc.20181211569
[Abstract](150) [FullText HTML](60) [PDF 997KB](1)
Abstract:
Beak is an important hard tissue of Cephalopoda which is usually used in the study of fisheries biology such as population identification, growth and stock assessment and so on. Based on the 860 samples of Sthenoteuthis oualaniensis collected by light falling-net fishery during May to August in the year of 2017 in the Xisha Islands waters of the South China Sea, the morphologic growth of beak impacted by gonad maturity and individual size was analyzed. The result of principal component analysis of twelve morphologic indices indicated that the upper hood length (UHL), upper crest length (UCL), upper rostrum width (URW), upper lateral wall length (ULWL), lower hood length (LHL), lower crest length (LCL),lower rostrum length (LRL) and the lower lateral wall length (LLWL) could be used to describe the length growth features of beak, and the HL/CL, URW/UCL, LRL/LCL, LWL/CL and WL/CL could be used as the indicators of entire growth of beak. The analysis of variance (ANOVA) and the least-significant difference (LSD) indicated that there were significant differences in the morphologic growth between sexes, gonad maturity and different mantle length, however the values of HL/CL, URW/UCL, LRL/LCL, LWL/CL and WL/CL were nearly constant with the change of sex, gonad maturity and mantle length. This study suggested that there are significant effects of gonad maturity and individual size on beak morphology and the mantle length of 121mm to 150 mm, the gonad maturity of Ⅲ seemed to be the inflection points of the morphologic growth beak of S. oualaniensis.
Effects of tea polyphenols on growth, antioxidant capacity and lipid metabolism related genes expression of turbot (Scophthalmus maximus)
Yicong LI, Kai LIAO, Renlei JI, Wei FANG, Dan XU, Kangsen MAI, Qinghu AI
In Press  doi: 10.11964/jfc.20180311205
[Abstract](2390) [FullText HTML](1283) [PDF 548KB](22)
Abstract:
In aquaculture, high fat diets are widely used for its protein sparing effect which can improve protein utilization efficiency, promote growth and protect environment pollution. Hoevever, it can also lead to excessive lipid deposition of liver and lower disease resistance. In order to solve this problem, additives should be explored. Tea polyphenols are natural plant extracts which have been proved to have the effects of of promoting growth, lipid reduction and immunity improving in many animals. Therefore, the purpose of the experiment is to investigate the effects of dietary tea polyphenols (TP) level on growth, antioxidant capacity and lipid metabolism of turbot. Four diets with graded levels of TP (0.00%, 0.01%, 0.02% and 0.05%. dry weight 0, 100, 200 and 500 mg/kg) was formulated in this experiment. Fish were cultured in indoor aquaculture system, and each diet was randomly assigned to three replicate groups of juvenile fish [initial average weight of (13.51+0.31) g] and fed twice daily (8:00, 18:00).The feeding trial lasted 70 d. The results showed as follows: ① Compared with the control group, fish fed the diet with 0.01%–0.02% TP had significantly higher weight gain rate (WGR). Feed efficiency (FE) was increased with the increasing TP level and no significant differences were detected among dietary treatments. Compared with the control group, Hepato-somatic index (HSI) was significantly increased by the supplement with TP. ② The lipid contents of whole fish and liver were decreased with increasing TP level and significantly lower in 0.02%–0.05% group compared with the control group. ③ Compared with the control group, the activities of total antioxidant capacity (T-AOC) and glutathione peroxidase (GSH-Px) were significantly higher in fish fed the diet with TP, and no significant differences were detected among fish fed diets with TP. The activity of superoxide dismutase (SOD) first increased and then decreased with the increasing TP level, and 0.02% supplement level was the highest. The content of malondialdehyde (MDA) was decreased with increasing TP level, and significantly higher in 0.02% group compared with the control group. ④ The expression of sterol regulatory element binding protein 1(SREBP-1) was decreased with increasing TP level and significantly higher in 0.02%–0.05% groups compared with the control group. The expression of fatty acid synthetase (FAS) was first decreased and then increased with increasing TP level and significantly lower in 0.02% group compared with the control group. The expression of peroxisome proliferator-activated receptor α (PPAR α) first increased and then decreased with increasing TP level and significantly higher in 0.02% group compared with the control group. The expression of carnitine palmitoyl transferase 1(CPT 1) increased with increasing TP level and significantly higher compared with the control group. This research indicated that high fat diets supplemented with TP could promote growth, reduce liver fat deposition, and increase antioxidant activity. The optimum supplemental level of TP in diets for turbot is approximatly 0.02%.
Nutritional components and mineral element distribution and health evaluation of back muscle of seven kinds of marine fish
Fangfang LIU, Shaoling YANG, Wanling LIN, Laihao LI, Xianqing YANG, Yanyan WU, Hui HUANG
In Press  doi: 10.11964/jfc.20180911450
[Abstract](1605) [FullText HTML](640) [PDF 668KB](9)
Abstract:
The basic nutrients, amino acid composition and mineral element content of seven kinds of marine fish were determined, and the amino acid was evaluated for nutrition. At the same time, the upper levels (UL) of nutrients were used to nutrition the mineral elements in fish muscles. Health risk analysis. The results showed that there were no significant differences in the crude ash content of the seven marine fishes, and the crude fat and water contents were significantly different. The Larimichthys had the highest crude fat content and the lowest water content, which were 9.44%±0.29% and 71.64%±0.44%, the Scarus ghobban had the highest water content, the lowest crude fat content, and the crude protein content was between (18.56%±0.29%) and (20.97%±0.32%), the difference was significant; 7 kinds of marine fish amino acid species Complete, and the ratio of ∑EAA/∑TAA and ∑EAA/∑NEAA is in line with the FAO/WHO ideal model, with the limiting amino acids Val, Trp, Met+Cys, and the essential amino acid index between 77.57 and 89.04; 7 tested seawaters The content of mineral elements in fish muscle was rich, and the content of the same elements in different fish species was significantly different. The average content of K element was the largest and the difference of Na element content was the most significant. The risk assessment of mineral elements showed that zhuhai sampling the maximum risk index of Cu in fish at 2-5, 6-17, 18-44, 45-59 is greater than 100%, which is an unacceptable risk range, and the average risk index is within the acceptable range. The above results are intended to provide a reference for the deep processing of marine fish and the daily diet of residents.
Effects of different cooking methods and in vitro simulated digestion on the immunoactivity of major allergen tropomyosin in Litopenaeus vannamei
Tianjiao HUANG, Mengmeng WANG, Yongyan GAO, Ying LU
In Press  doi: 10.11964/jfc.20181211594
[Abstract](1348) [FullText HTML](630) [PDF 881KB](2)
Abstract:
In this study, the cooking methods of boiled, fried and braised were used to treat the meat of Litopenaeus vannamei, and the cooked shrimp was subjected to in vitro simulated saliva-gastric-intestinal digestion to investigate the immunological activity after cooking. Changes of major allergen tropomyosin in shrimp were analyzed by SDS-PAGE, Western-blotting and indirect ELISA. The results of SDS-PAGE showed that there was no significant change in the TM bands by three cooking methods, indicating that the TM did not undergo degradation during cooking; the results of immunoblotting and indirect ELISA showed that the immunological activity of TM in boiled, fried and braised were lost 2.08%, 11.33% and 15.56%, respectively. However, the immunological activity of the in vitro simulated digestion products of shrimp meat after cooking was significantly lost, and the immunological activitiy of boiled, fried and braised were decreased by 86.90%, 88.94% and 97.39%, respectively. Studies have shown that the reduction of shrimp TM immunological activity mainly occurs in the simulated intestinal fluid digestion stage, three cooking treatments can reduce the immunological activity of TM, and the brazing treatment makes the reduction of TM immunological activity most obvious. This experiment provides a theoretical basis for the study of allergen reduction mechanism and the development of hypoallergenic aquatic products.
Polymorphism in CgTyr1 gene and its association with shell color traits in the Pacific oyster (Crassostrea gigas)
Bowen ZHAO, Qi LI, Jiulong WANG, Hong YU
In Press  doi: 10.11964/jfc.20181211559
[Abstract](1151) [FullText HTML](613) [PDF 671KB](5)
Abstract:
The Pacific oyster Crassostrea gigas is cultured worldwide due to the advantages of rapid growth and good adaptability, and has become one of the most commercially important bivalve species. In our successively selective breeding, three strains of C. gigas with black, white and gold shell color traits have been developed. Tyrosinase (Tyr) is known as one of the most important enzymes in the regulation and production of melanin in animals. In this study, exons in the C. gigas TYR gene (CgTyr1) were sequenced. Mutations of the CgTyr1 gene and its association with shell color were analyzed in the three shell color strains of C. gigas. A total of 23 single nucleotide polymorphisms (SNP) were detected using single-strand conformation polymorphism (SSCP) and sequencing analysis, of which 11 SNP loci were highly significant difference between the three shell-color strains. In the SNP loci with significant difference, mutation c.591C/T, c.632G/A and c.1155T/C are non-synonymous which lead to amino acid changes Ala122Val, Gly136Ser and Phe310Ser. For further analysis, 11 SNP loci with a highly significant difference were selected for haplotype construction. One specific haplotype for every shell color strain was constructed and confirmed in the validating group. The mutations and haplotypes that are strongly associated with the shell color phenotypes in this study could be useful in understanding the molecular mechanism of pigmentation, and potentially applied to marker-assisted selection breeding programs for C. gigas.
Effects of dietary selenium levels on growth performance, antioxidant capacity and related gene expression of juvenile turbot(Scophthalmus maximus) under copper stress
Tiantian HAO, Jiying WANG, Changxing MA, Ying ZHOU, Baoshan LI, Chengqiang WANG, Yongzhi SUN, Bingshan HUANG
In Press  doi: 10.11964/jfc.20181011515
[Abstract](1311) [FullText HTML](641) [PDF 767KB](10)
Abstract:
The study was carried out to investigate the effect of dietary selenium(Se) supplementation on the growth performance, serum antioxidant enzyme activity and expression of related genes in liver of juvenile turbot(Scophthalmus maximus) under copper(Cu) stress. Four experimental diets(D1,D2,D3,D4) were formulated to contain the following diets with increment levels of copper 0, 1 000, 1 000, 1 000 mg/kg, and selenium 0, 0, 2, 4 mg/kg. The group D1 as the control. Each diet was randomly assigned to triplicate groups of 40 fish [initial weight, (24.85±0.1) g] per aquarium. Fish were fed twice daily(8:30 and 16:30) at ratio of 1.5% or 2% body weight for 84 days. Results showed that the different diets had no significant effect on the survival rate of turbot. The weight gain rate, specific growth rate and protein efficiency ratio of D2 group was significantly lower than other groups. Whereas, feed conversion ratio and feed intake reached the maximum in group D2. Crude lipid content of whole body and liver all showed a trend of first decreasing and then rising, Whereas, there were no significant difference of crude lipid and crude protein content in muscle among all groups. Cu concentration of D2 group in whole body, vertebra and liver was remarkably higher than the others. Whereas, Zn concentration in whole body, vertebra and liver reached the maximum in the group D4. Hepatic Fe concentration was lower in group D4 than the others. The serum total antioxidant capacity activity, Catalase activity, glutathione peroxidase activity decreased in group D2, and increased with further increase of selenium level. While the malondialdehyde content followed the opposite pattern. Total superoxide dismutase and CuZn superoxide dismutase activity both of them reached the minimum in group D4. Both alanine aminotransferase and aspartate transaminase activities showed their highest values in group D2, which were significantly higher than those in the other groups. Glucose, triglyceride, total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol showed a opposite trend with alanine aminotransferase and aspartate transaminase activities with the lowest value in group D2, significantly lower than that in the control group. Metallothionein expression increased in the liver with the dietary selenium levels under Cu stress, which was significantly higher in group D4 than that in the other groups. Glutathione transferase and lysozyme expression levels decreased initially and then increased with the dietary change, which were significantly lower in group D2 than those in the control group. Whereas heat shock protein 70(HSP70) expression level showed the highest values in group D2, which was significantly higher than those in the other groups. In conclusion, adequate dietary selenium levels could affect the growth performance, increase the total antioxidant capacities, modulate some mRNA expression of gene in liver, and then reduce the metabolic disorders caused by high copper content in juvenile S. maximus.
Cloning and distribution of histone H2A during spermatogenesis of the Chinese mitten crab, Eriocheir sinensis
Jiangli WU, Tingrong Chen, Shumei MU, Han ZHANG, Xianjiang KANG
Accepted Manuscript  doi: 10.11964/jfc.20190311691
[Abstract](106) [FullText HTML](68) [PDF 1149KB](0)
Abstract:
Spermatogenesis is the process by which spermatogonia develop into mature spermatozoa. In most animals, this process involves changes in the basic protein associated with DNA. Somatic-type histones are partially or totally replaced by transition proteins, which in turn are replaced by protamines with strong alkaline. With the replacement of basic proteins, nuclei progressively undergo chromatin condensation. The Chinese mitten crab (Eriocheir sinensis) sperm nucleus chromatin arrange loosely, its formation is not clear. In this research, DNA sequence encoding histone H2A was cloned by PCR method. Thereafter, polyclonal antibody against the histone H2A was generated in rabbit, histone H2A distribution during E. sinensis spermatogenesis was detected through immunofluorescence. The encoding sequence of E. sinensis H2A contains 369 bp that encodes a protein of 123 amino acids. The predicted molecular weight of H2A was 13.1 ku. Protein alignment studies demonstrated that this histone H2A had a high identity with its counterparts in Penaeus vannmei and P.monodon, and the homology both are 99.19%. Immunofluorescence demonstrated that histone H2A was present through the spermatogenesis of E.sinensis. In spermatogonia and spermatocytes, H2A was mainly distributed in the nuclei and cytoplasm, while in spermatids and spermatozoa, H2A was mainly in the nuclei. The persistence of H2A in the mature sperm nucleus of E. sinensis might have some association with the uncondensed chromatin.
Effects of an artificial reef on diel changes of micro- and meso-zooplankton
Feiyang DU, Lianggen WANG, Ling DING, Jiajia NING, Yafang LI, Lei XU, Delian HUANG, Xiaoping JIA
In Press  doi: 10.11964/jfc.20190711859
[Abstract](240) [FullText HTML](144) [PDF 817KB](5)
Abstract:
The apparent diurnal vertical migration of zooplanktons leads to diurnal vertical migration of certain fishes that feed on zooplanktons. In order to investigate the effects of an artificial reef on diurnal vertical migration of micro- and meso-zooplankton, we obtained 14 zooplankton samples from diurnal sampling in and outside an artificial reef area in the coastal Fangchenggang City, Guangxi Autonomous Region in November, 2018. The analysis showed that zooplankton compositions were quite similar between the artificial reef site and the control site, with the low species replacement rate and the same dominant species, indicating that the zooplanktons come from a same faunal assemblage. However, influenced by the flow-field effect of an artificial reef, zooplankton abundance and diversity were higher at the reef site than those at the control site. At the control site, zooplankton abundance showed apparent diurnal changes following a sinusoidal trend, with the highest abundance at 16:00 and the lowest at 04:00. There was apparent vertical migration between 4:00 and 20:00, while zooplankton abundance was quite stable from 20:00 to 4:00. At the reef site, due to the effect of horizontal fast flow field above the reef, zooplankton abundance fluctuated with time and no apparent diurnal vertical rhythm was observed. It is believed that higher zooplankton abundance above an artificial reef would enhance the reef’s fish-aggregating effect and promote the conversion of zooplankton productivity to fish. Cluster analysis and ordination of the 14 zooplankton samples identified one sample group for the reef site, but two sample groups for the control site, one being mainly composed of phytoplankton feeders following the upward shifts of phytoplankton during the daytime, the other being mainly composed of carnivorous species during nighttime after the phytoplankton feeders migrating downward.
Ecological function of seaweed-formed habitat and discussion of its application to sea ranching
Shouyu ZHANG, Shurong LIU, Xijie Zhou, Zhenhua Wang, Kai Wang
In Press  doi: 10.11964/jfc.20190711873
[Abstract](511) [FullText HTML](158) [PDF 734KB](5)
Abstract:
Seaweed is the one of the most important coastal ecosystem-engineers, and the habitat formed by it plays an important role in supporting ecological behaviors (e.g. feeding, growth and recruitment, etc) of marine organisms.. However, seaweed beds are declining around the world since the environmental changes and human activities, which makes non-negligible impact on organisms inhabited there. China suffered severely from this situation. To achieve the goal of sustainable utilization of marine resources, the restoration of seaweed beds is becoming an important assignment of China’s ecological environment protection in coastal areas. However, the lack of understanding of ecological function of seaweed and seaweed-formed habitat makes the objectives and methods of the seaweed beds restoration are not clear. In this paper, we summarized the ecological function of seaweed and seaweed-formed habitat, such as seaweed beds and seaweed farming area in the context of ecological restoration of seaweed beds. Furthermore, we proposed some thoughts about whether it’s suitable for the seaweed farming be incorporated into the construction of sea ranching. We also suggested some quantitative measurements of ecological function in seaweed-formed habitat. Our analysis may provide references for restoring seaweed beds reasonably and efficiently, and sustainable development of seaweed farming industry in the future.
Recombinant expression and bioactivity analysis of two leptin genes of Cynoglossus Semilaevis
Yaxing ZHANG, Bin WANG, Xuezhou LIU, Yongjiang XU, Bao SHI, Yan JIANG, Aijun CUI, Zhengrong ZHANG, Ranran SUN
Accepted Manuscript  doi: 10.11964/jfc.20181211598
[Abstract](150) [FullText HTML](94) [PDF 1106KB](3)
Abstract:
The peptides encoding ORF domains were synthesized based on the amino acid sequence of lepa and lepb from Cynoglossus semilaevis. The prokaryotic expression vector pEQ30 was used to construct the recombinant plasmids of lepa/pQE30 and lepb/pQE30, which were transformed into Escherichia coli M15 strains and then induced by IPTG to obtain the recombinant proteins of LepA and LepB containing His 6 at the N-terminus. The obtained LepA and LepB polypeptides expressed in form of inclusion bodies with molecular weight were both 16 ku, and the optimum condition for the highest expression of the target proteins were induction by 0.5 mmol/L IPTG at 37 °C for 4 hours. The concentrations of LepA and LepB recombinant proteins in tongue sole were 0.3 mg/mL and 0.25 mg/mL, respectively. The results of Western Blot and mass spectrometry analysis indicated that the obtained recombinant proteins of LepA and LepB had correct sequences and immunological activity. The proteins were purified by Ni2+-NTA affinity chromatography, and high-purity recombinant proteins of LepA and LepB were obtained. In vitro incubation of hypothalamus with recombinant LepA and LepB proteins from C. semilaevis indicated that they could significantly inhibit the expression of endogenous lepalepb and gnrh3 mRNA, which verified that the obtained recombinant proteins have biological activities. The results could support exploration of the physiological role and regulation mechanism of leptin in growth and development of C. semilaevis.
Review on development, definition and classification of marine ranching in domestic and overseas
Pimao CHEN, Liming SHU, Huarong YUAN, Xue FENG, Fei TONG, Quan CHEN, Yuxiang CHEN, Jie YU, Guobao CHEN, Jing YU, Lei ZENG, Xiaoguo LI
In Press  doi: 10.11964/jfc.20190711887
[Abstract](1786) [FullText HTML](228) [PDF 871KB](13)
Abstract:
Marine ranching is a long-term and world-widely used marine fishery development measure. This paper reviewed the development of marine ranching around the world as well as the existed definitions and classifications. Outside China, fishery resources enhancement is generally regarded as marine ranching. Since the 1940s, the artificial reef has expanded from the simple fish aggregation to the protection and restoration of marine ranching habitat, and aimed to the increase and utilization of fishery resources. In northeast Asian, such as Japan and South Korea, the objective of constructing artificial reefs is to increase aggregate and catch fishery resources on large scales; and many countries in Europe and America build artificial reefs to increase and protect fishery resources and develop recreational fishery. Overall, the overseas marine ranching construction with fishery resources enhancement as the main purpose has both successes and failures, whereas the successful experience is worth our learning. The overseas definitions and classifications of marine ranching are few, the definition is presented and used in a more rigorous way. China paid much attention to the development of marine ranching in recent years, and supported it as an important means for aquatic biological resources conservation, fishermen industrial upgrading, and marine ecology civilization construction. Great progress has been made in the construction scale, output effect, technical level and development mechanism of marine ranching. However, the industry and sci-technology are still in the initial stage, and facing a series of problems to be solved urgently due to the late start. Range from 1960s to 1970s, Chinese scholars have proposed the concepts of marine ranching and marine farming and ranching, and made a distinction between the two definitions. Subsequently, many scholars equated the enhancement of fishery resources with marine ranching. Recently, the development of marine ranching is hot in China, but the definition of marine ranching is non-standard, such as numerous definitions, meaningless definitions, and lacking precise definitions. Finally, this paper summarized and prospected the development trend, development concept, target positioning, construction content, research support and other aspects of marine ranching. Grasping the development philosophy, positioning, content and goal of marine ranching rationally and practically, to strengthen the publicity of the existing Marine ranching industry standards, especially the definition and classification, and guide the orderly development of Marine ranching research and construction work, which is the key for effectively supporting the healthy development of marine ranching.
Flow field efficiency of Mi-zi artificial reefs in different construction modes based on numerical experiments
Yu GUO, Shouyu ZHANG, Jun LIN
In Press  doi: 10.11964/jfc.20190511800
[Abstract](979) [FullText HTML](519) [PDF 2595KB](8)
Abstract:
The throwing scale of artificial reefs is one of the core issues in the construction of reefs. The throwing amount and disposal spacing of artificial reefs not only characterize the range and density, but also determine the efficiency of artificial reefs flow field effects. In our study, the flow field characteristics of seven disposal spacing (0 l, 0.5 l, 1.0 l, 1.5 l, 2.0 l, 3.0 l and 4.0 l) that is the multiple of the length of the single artificial reefs, with four throwing amounts of Mi-zi artificial reefs (2×2, 3×3, 4×4 and 5×5) were simulated using the large eddy simulation model based on the ANSYS software. Then, the relationships between the characteristics (including the relative volume, relative height and relative length) of different flow fields and the throwing amounts and disposal spacing and the target velocity ratio were studied. The results showed that when the upwelling target velocity ratio is less than 0.10, 0.10 to 0.15 and greater than 0.15 times, the maximum disposal spacing is 4.0 l, 3.0 l, 2.0 l, respectively, and there was a synergistic effect on the upwelling area. And the maximum disposal spacing is 3.0 l at all the back eddy target velocity ratios. The larger the reefing amount is, the higher the relative volume both the upwelling and the back eddy are, and the lower the average relative volume growth rate. At the disposal spacing of 0.5 l, the relative upwelling volume and the relative volume of the single artificial reefs are the largest, but the back eddy relative volume and the relative volume of the single artificial reefs are the largest at 1.5 l. The upwelling’s relative height increased at a rate of 1.01 times with the laying amount increasing and decreased at a rate of 0.90 times with the disposal spacing increasing, while the relative length of the back eddy would increase firstly and then decrease with the disposal spacing and the maximum at 1.0 l. The study provides the theoretical planning guidance for the artificial reef placement in different construction modes.
Structural design principle and research progress of artificial reef
Zhaoyang JIANG, Zhansheng GUO, Lixin ZHU, Zhenlin LIANG
In Press  doi: 10.11964/jfc.20190711889
[Abstract](338) [FullText HTML](206) [PDF 975KB](5)
Abstract:
At present, there is no clear principle and basis for the structural design of artificial reefs. This paper expounds the basic principle of artificial reef structure design from the point of view of flow field effect, biological effect and shelter effect, illustrates the relevant basis and methods with examples, and summarizes and analyses the construction mode and future development of artificial reef area suitable for different types of sea area, in order to provide reference for the structural design of artificial reefs and the planning of marine ranching.
Assessment to the speciation and vertical distribution characteristics of heavy metals in core sediments in marine ranching of Ma′an Archipelago
Yiqian SHI, Xu ZHAO, Jinchen YU, Jun LIN, Xingyu HAN, Zhen LIU, Hong HUANG
In Press  doi: 10.11964/jfc.20190511821
[Abstract](1425) [FullText HTML](606) [PDF 1002KB](12)
Abstract:
In order to understand the characteristics of speciation and vertical distribution of heavy metals in the sediments, columnar sediments were collected in surrounding water of Ma′an Archipelago in June 2018. Seven heavy metals (Cd, Cu, Zn, Pb, Cr, As, Ni) were analyzed, with the improved European Community Bureau of Reference (BCR) method, by measuring the grain size composition of columnar sediments, and the vertical distribution characteristics and sources of heavy metals in the sediment of Ma′an Archipelago, by combining the analyzing method, Igeo, correlation and potential ecological risk index, were explored. The results showed that fine silt (D [3,2]) was dominant in the columnar samples; the content of heavy metals in the columnar samples fluctuated serrated with depth. The total amount of seven heavy metals reached the peak at 0.5 m and 2.0 m; all of them reached the class I standard of marine sediment quality in China; Cd was dominated by secondary phase, which was composed of the exchangeable and carbonate fractions (F1)、iron-manganese oxide states (F2) and organic matter and sulfide fractions (F3), The proportion of three fractions is similar; the mode of occurrence of Cu, Zn, Pb, Cr, As, Ni were residual state, and the trend of effective state of seven heavy metals was periodic and consistent. Take Ni as a reference, with three analytical methods, results showed that Cu, Zn, Pb, Cr, As and Ni are mainly natural deposition, and whether Cd is a threat to the environment still remains to further study. Through three analytical methods, we can observe the content and morphology changing by years of heavy metals by means of isotope dating, aiming to determine the historical records and influencing factors of heavy metal pollution. The pollution degree of heavy metals in surrounding water near Ma'an Archipelago is much lower, and the ecological environment is totally well protected, of which the environment is accurately, less affected by human factors, reflecting the results of local sediment background values.
Community structure of fish eggs and larvae in artificial reef area of Ma’an Archipelago
Rui YIN, Rijin JIANG, Yuanxin BI, Linlin ZHANG, Ziwei FAN, Lei CHEN, Youzhen SUI, Shicong WANG
In Press  doi: 10.11964/jfc.20190411761
[Abstract](1046) [FullText HTML](526) [PDF 1080KB](22)
Abstract:
With the aim of understanding the impact of artificial reef deployment on the distribution of fish eggs and larvae, a horizontal trawl survey using large plankton nets in Ma’an Archipelago from January 2018 to October 2018 was carried out on four voyages. According to the species composition, quantity distribution and other community structure characteristics of fish eggs and larvae, their resource distribution in reef areas and natural areas were studied.The results showed that a total of 5 642 fish eggs and 1 013 larvae were collected, which belonged to 10 orders, 21 families and 49 species. Harpodonle sueur, Cynoglossus joyneri and Larimichthys polyactis were dominant fish eggs; Sebastiscus marmoratus, Lateolabrax japonicus and Stolephorus sp. were the dominant fish larvae. The dominant species of fish eggs and larvae in the reef area and the natural area were almost the same, while the community structure was significantly different. The reef areas had significant differences with the natural areas in the biodiversity, and the diversity index, richness index and evenness index of the reef area were highest in spring. Cluster analysis indicated that the community structure of fish eggs and larvae were the most stable in spring, the simplest in winter, and the summer had the higher similarity with autumn. Comprehensive analysis suggested that artificial reefs in Ma’an Archipelago have certain aggregation and shelter effects on fish eggs and larvae, and the marine physical environmental factors such as temperature (T), salinity (S), water turbidity (Turb.) and so on have significant effects on the distribution of fish eggs and larvae.
ScHsc70 gene SNP markers screening and correlation analysis for high temperature resistance of Sinonovacula constricta new variety “Shenzhe NO. 1”
Baobao XUE, Delong MENG, Shuyu REN, Benlong SHEN, Donghong NIU, Jiale LI, Heding SHEN
Accepted Manuscript  doi: 10.11964/jfc.20181111527
[Abstract](1213) [FullText HTML](606) [PDF 756KB](20)
Abstract:
To obtain single nucleotide polymorphism (SNP) markers of heat shock protein 70 (ScHsc70) gene related to heat tolerance traits in Sinonovacula constricta. In this study, the full-length sequence of ScHsc70 gene was cloned by direct sequencing. The length was 4 048 bp, including 6 introns and 7 exons, and the coding region was 1 950 bp. Under heat stress high temperature resistance groups and control groups from a new variety of razor clam were established six potential SNPs Rs1 (g.588 C > T), Rs2 (g.840 C > T), Rs3 (g.885 T > A), Rs4 (g.1233 A > G), Rs5 (g.1467 T > G), Rs6 (g.1482 T > C) were screened from the exon region of ScHSc70 gene by PCR product direct sequencing. SNPs genotyping was performed on the high temperature tolerant population and the control population of the new variety " Shenzhe No.1” by Sanger sequencing. The results of genetic diversity analysis showed that the polymorphism information content (PIC) of the two populations was between 0.111 2 and 0.371 8, and the average polymorphism information content of the control population was 0.267 0, which is higher than that of the high temperature resistant populations (0.223 65). Association analysis results showed that the genotype frequency and allele frequency of Rs1, Rs3 and Rs4 were significantly different between control group and high temperature tolerant group. Haploid linkage disequilibrium analysis showed that SNPs markers of ScHsc70 gene could form 2 haploid blocks and 7 haplotypes, among which CCT haplotypes were significantly correlated with high temperature tolerance traits. It was found that Rs2 and Rs3 were in a linkage state (r2 = 0.86, LOD = 25.56, D = 1.0), and could be used as SNP markers for the Genetic breeding of S. constricta for high temperature tolerance. In summary, Rs1, Rs3, Rs4 and haplotype CCT can be used as candidate auxiliary molecular markers for high temperature tolerance breeding of razor clam, which lays a theoretical foundation for the subsequent functional verification of resistance-related SNPs.
Static accumulation of two artificial reef monomer models
Shouyu ZHANG, Yunsong XIAO, Jun LIN, Xijie ZHOU, Yu GUO
In Press  doi: 10.11964/jfc.20190511775
[Abstract](432) [FullText HTML](292) [PDF 1268KB](3)
Abstract:
The trend of artificial reefs construction in China have following two aspects: firstly, using large-scale artificial reef construction project to enhance the ecological effect of hard substrate, and secondly, using offshore artificial reef construction to extend the stock enhancement function of hard substrate. Static accumulation experiment was conducted to analysis the stacking effect and performance of regular frame reef monomer and HUT reef monomer, which are commonly used for offshore reef mountain construction in China. In views of the structure and shape of reef monomer, the index of coefficients, such as the volume growth rate, the volume ratio and stack slope angle of the two monomers (regular frame reef monomer vs. HUT reef monomer) models in the experiment were compared. Also, we compared the change of efficiency in different quantity between two monomers. The results showed that: ①under the same quantity monomer condition model, the volume growth rate of the regular frame reef monomer is higher than that of the HUT reef monomer, and the scale and bottom area of the artificial mound are relatively higher(HUT: 9.783±0.039 vs. regular frame reef: 7.799±0.057). This result demonstrated that regular frame reef monomer is more appropriate for artificial reef construction in slow current and shallow water. While the Volume rate of the HUT monomer forming-mound structure is higher than that of the regular frame reef forming-mound structure. This result showed that HUT reef monomer forming mound is relatively taller and more permeable, which is more appropriate for offshore artificial reef construction project. ② From the perspective of the height contribution rate of two types of monomer mound, and the difference of the characteristics of the two monomers is fully demonstrated in our study. Specifically, to achieve effective physical effect of artificial reef mound, the minimum number of regular frame reef unit is 28 while the HUT reef unit is 40.
Habitat use of juvenile rockfish Sebastiscus marmoratus in mussel farming waters: a preliminary study
Zhenhua WANG, Jiaming ZHONG, Shouyu ZHANG, Kai WANG, Jun LIN, Jian ZHANG, Hui SHEN
Accepted Manuscript  doi: 10.11964/jfc.20190611831
[Abstract](445) [FullText HTML](283) [PDF 1265KB](9)
Abstract:
Mussel farming habitat distributed in Shengsi archipelago has growing in scales since last century and playing parts of key roles as marine ranching. Fully understanding on habitat use strategies of rock fishes in mussel farming area can be important reference as design of marine ranching programs. A monthly survey targeted on juvenile rockfish Sebastiscus marmoratus was carried out from May to July, 2018 in the northern area of Zhoushan archipelago, in order to explore the habitat use characteristics of juvenile Rockfish in mussel farming area, as well as its reference value for marine ranching projects. Self-designed nets were applied to collect juvenile rockfish. Inhabitant density and its spatial distribution characteristics, habitat selection strategies, food selection characteristics based on stomach contents analysis, and early life cycles based on otolith rings, were discussed. The inhabitant density for juvenile rockfish from May to July was respectively (10±6) inds/string, (7±5) inds/string and (5±5) inds/string, which showing a monthly decline trend. Juvenile individuals distributed widely during early month and then moved from offshore side of mussel farming area toward inshore side till its complete disappearance in offshore sites. However, sites with the greatest densities were always located besides shoreline area. Positive correlation was detected between juvenile densities and void volume as well as macroalgae biomass from hanging mussel strings base on correlation analysis, although not in significant level. High feeding intensity lasted all three months with zero rate of empty stomachs, were revealed by stomach content analysis. The average feeding degree was higher in mussel farming area than that in the rocky reef habitat. The juvenile rockfish mainly feed on Amphipoda represented by Caprellidae sp.and Gammaridea sp, which account 99.2% together by weight among its total diet composition. Its early stage inhabited in mussel farming habitat lasted about two to three months with average daily growth ring equal to (57±12) d for juvenile rockfish. Comparison of homogeneousness and regularity on otolith rings revealed that individuals inhabited in mussel farming area showing much more consistence than those from rocky reef habitats. It is indicated that hanging strings in mussel farming waters around Gouqi Island has supplied idea habitats to juvenile rockfish by offering much more stable physical environment and abundant food sources, which in turn made great contributions to its stock enhancement and population conservation effects in local areas. It is suggested that local government should pay close attention to habitat use strategies of dominant reef fishes such as rockfish by means of applying suspended structures on proper scales in local marine ranching programs.
Water environment carrying capacity of Haizhou Bay marine ranching
Jinchen YU, Na LI, Shuo ZHANG, Xu ZHAO, Yan LAN, Yilin LIU, Hong HUANG
Accepted Manuscript  doi: 10.11964/jfc.20190611824
[Abstract](539) [FullText HTML](358) [PDF 940KB](8)
Abstract:
Marine ranching is an important measure to achieve marine environmental protection and efficient production of fishery resources. Based on the water environment data of Haizhou Bay marine ranching demonstration area in spring (May), summer (August) and autumn (October) of 2014, selecting permanganate index (CODMn), dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), biochemical oxygen demand (BOD) as evaluation indexes, neural network models were developed using BP (back propagation) to evaluate the water environmental carrying capacity of the area. The results showed that the average water environmental carrying capacity index of Haizhou Bay marine ranching in 2014 was higher than 0.6, indicating an ideal level of the carrying status. Water environmental carrying capacity varied seasonally as follows: summer > spring > autumn. The water environmental carrying capacity of marine ranching area was obviously better than that of the control area. The high concentrations of CODMn and DIN were the main reason for the slight overload of some stations, which might be related to land-based pollution. In addition, shipping water also had a certain negative impact on the water environment. BP neural network model has the advantages of convenient construction, objective and reasonable evaluation results, which could be applied to the study of water environmental carrying capacity in marine pastures and other sea areas.
Present situation and future development of marine ranching construction in China
Zhongyi LI, Qun LIN, Jiao LI, Xiujuan SHAN
In Press  doi: 10.11964/jfc.20190311699
[Abstract](663) [FullText HTML](364) [PDF 692KB](26)
Abstract:
This paper reviewed the works about marine ranching researches in China from its construction, including introduction of the background and necessity of marine ranching construction in China, and summarizes of research process, research content and current basic state of the marine ranching in China. At the same time, we reviewed the works about research content and development process of marine ranching in foreign countries, especially summarized the research experience of marine ranching in Japan. From their research works about marine ranching, researcher of these foreign countries concluded that the ultimate goal of marine ranching construction was to recovery its natural ecosystem. The current research works of marine ranching in China were focused on their own construction of marine ranching and the population restoration of the enhancement and releasing species. Although there were some researches about the ecological system of marine ranching in China, most of them stayed in the primary research stage, without depth and accuracy. Many research parameters of these research works were introduced from the results of other research works, with no consideration of the differences between natural and artificial sea areas, and the regional differences among marine ranching. The future focus of research work about marine ranching in China should be concentrated on the works about the food web and energy flow of marine ranching’s ecosystem, in order to promote the production of marine ranching, provide a scientific basis for the study of natural nutrient channels between artificial reef areas and surrounding waters for ecosystem construction.
Distribution characteristics of Liza haematocheila and its relationship with environmental factors on Furongdao artificial reefs, Laizhou Bay, China
Xinmeng WANG, Huaxiang SHENG, Shude LIU, Guangjie FANG, Haolin YU, Yanli TANG, Zhenlin Liang
In Press  doi: 10.11964/jfc.20190511818
[Abstract](1048) [FullText HTML](493) [PDF 1347KB](17)
Abstract:
Abundance of Liza haematocheila has declined rapidly since the 1980 s in Bohai Sea, due to the increasingly fishing pressure caused by the change of fishery methods. Furongdao artificial reefs (ARs), located in Laizhou Bay, has provided a good habitat for L. haematocheila, making it one of the major fish resources in the AR area. In order to explore the response of L. haematocheila to environmental factors, the effect of environmental factors, artificial reefs, food abundance on CPUE and mean standard length of Liza haematocheila were analyzed using GAM model. L. haematocheila were collected by trammels survey of Furongdao ARs during 2014-2017. The results showed that there is no significant difference between average CPUE values of artificial reef area and natural area in spring (P = 0.362), however, the CPUE in AR area is 3.53 times of CPUE in the control area in the Autumn. Three-way ANOVA showed that CPUE is significantly affected by year, month, artificial reefs and interaction effect of year and month (P < 0.01). Average length was affected by year (P < 0.01). Results of Delta GAM showed that the probability that L. haematocheila occurs was significantly influenced by temperature and whether the site is in the AR area. The probability of presence is higher in AR area than in the natural area. As temperature increase, probability of presence decreases. CPUE increases when temperature is below than 8 °C, and then decreases. Mean standard length of L. haematocheila is influenced by abundance of Bacillariophyta and zooplankton. When abundance of Bacillariophyta is smaller than 3×105 cells/m3, mean standard length decreases with the increase of the abundance of Bacillariophyta, and then doesn’t change. Mean standard length decreases with abundance of zooplankton rises. In conclusion, L. haematocheila is mainly distributed in the AR area as low temperature, and large fish is mainly distributed in the area with low abundance of Bacillariophyta and zooplankton.
Isolation, identification and characteristics of pathogenic bacteria from Paralichthys olivaceus with ascites
Kun SHANG, Lingyun QU, Yufen WANG, Bin WANG, Han ZHAO, Ping GAO, Xin LIU
Accepted Manuscript  doi: 10.11964/jfc.20181211590
[Abstract](864) [FullText HTML](413) [PDF 1120KB](17)
Abstract:
In order to determine the pathogen, which can cause the death of cultured Paralichthys olivaceus from ascites disease in Beidaihe area, Hebei Province, three dominant bacteria were isolated from P.olivaceus infected with ascites. The biological status of the isolates was determined by physiological and biochemical identification and 16S rRNA sequence alignment. The pathological characteristics of the isolates were further identified by virulence genes (toxR, vhhA, vhhB) and histopathological analysis. The results showed that the three isolates were Vibrio harveyi and the virulence genes of the three isolates were all positive. Pathological sections showed that the isolates could be used to treat multiple organs (intestine, kidney, spleen and liver) of P.olivaceus. The LD50 of strain BDHYPFS-Y1G to P.olivaceus was 5.88×106 CFU/g, which was lower than the toxicity of natural state. Drug susceptibility test indicated that all three isolates were highly sensitive to the nitrofurantoin. This study confirmed the pathogen of this ascites disease, and preliminarily studied the pathogenicity and drug sensitivity of the pathogen, which can provide scientific basis for the prevention and control of the disease in industrial culture of flounder.
Isolation, Identification and Histopathological study on lethal sarcoidosis of Micropterus salmoides
Shengyu HE, Wenyan WEI, Tao LIU, Qian YANG, Heng XIE, Qiyao HE, Kaiyu WANG
Accepted Manuscript  doi: 10.11964/jfc.20181011495
[Abstract](704) [FullText HTML](423) [PDF 1520KB](14)
Abstract:
In April 2018, a large number of largemouth bass (Micropterus salmoides) were infected with lethal sarcoidosis in a farm in Qionglai, Sichuan Province. In order to define the potential pathogens, a bacterial strain named HSY-NS02 was isolated from skin ulcers, effusions from fish swimming bladder’s cavity and liver of the diseased Micropterus salmoides by traditional pathogen isolation methods. The strain HSY-NS02 was identified as Nocardia seriolea by means of morphologic structure and dyeing observation, PCR amplification and sequence analysis of 16S rRNA gene and specific primer, constructing phylogenetic tree, physiological and biochemical test. Furthermore, the pathogenicity of the strain HSY-NS02 was confirmed by the infection experiment in healthy largemouth bass,which’s results showed that the strain HSY-NS02 was cofirmed to be pathogenic to healthy largemouth bass and the same bacterium could be recovered from these infected largemouth bass. Histopathological observation and analysis of diseased largemouth bass showed that there were different degrees of chronic granulomatous lesions in skin ulcers, heart, liver, spleen, kidney and gill, of which spleen lesions were the most serious. the antibiotic susceptibility of the strain HSY-NS02 was carried out to guide the clinically choosing medicine, and the results showed that the strain was sensitive to gentamicin, neomycin and nystatin, but resistant to other 18 kinds of antibiotics, which implied the strain HSY-NS02 was resistant to multiple antibiotics.
Comparative chromosome mapping of 45S rDNA in four species of abalone
Jianpeng ZHANG, Tongyi WANG, Xuan LUO, Weiwei YOU, Caihuan KE, Mingyi CAI
Accepted Manuscript  doi: 10.11964/jfc.20181211591
[Abstract](1123) [FullText HTML](403) [PDF 808KB](1)
Abstract:
Abalone is not only precious seafood in China, but also important mariculture shellfish. In recent years, the genetic breeding research of abalone has made rapid progress, but the research data of cytogenetic analysis is still in lack. Therefore, this study used the fluorescence in situ hybridization (FISH) to compare the distribution of 45S rDNA clusters in Haliotis discus hannai, H. gigantea, H. fulgens, and H. diversicolor. In H. discus hannai, 83% of the metaphase had 2 pairs of 45S rDNA sites, locating at terminal of the long arm ends of chromosomes 13th and 16th, respectively. In H. gigantea, about 75% of the metaphase had 3 pairs of 45S rDNA sites, locating at the terminal of the short arm of chromosome 6th, and at the terminal of the long arm of chromosomes 14th and 17th, respectively. In H. fulgens, about 85% of the metaphase cells detected three pairs of 45S rDNA sites located at the terminal of the long arms of chromosomes 4th, 6th, and 8th. In H. diversicolor, about 65% of the metaphase had 3 pairs of 45S rDNA sites, locating at the terminal of the short arms of chromosomes 3th, 4th, and 12th. In addition to the main mode, there were other low-frequency modes in all the 4 species of abalone, suggesting that these abalone may have several unstable 45S rDNA sites besides the unambiguous sites. The number and the location of 45S rDNA loci in abalone showed a high level of intraspecific variation in general. These findings enrich the cytogenetic research data of abalone and provide basic data for the further studies of genetic breeding in abalone.
Response of lysozyme activity to Vibrio anguillarum infection in different tissues of Scapharca broughtonii
Dan ZHAO, Liqing ZHOU, Biao WU, Xiujun SUN, Feng ZHAO, Aiguo YANG, Zhihong LIU, Qing ZHAO, Gaowei ZHANG, Xi CHEN
Accepted Manuscript  doi: 10.11964/jfc.20181211570
[Abstract](1010) [FullText HTML](457) [PDF 1186KB](1)
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The changes in the marine environment and overfishing have caused imbalances in the ecological environment, making the various diseases of shellfish increasingly prominent, and the diseases caused by pathogenic Vibrio have become more common. In this context, the number of wild resources of Scapharca broughtonii has been sharply reduced, and its breeding industry is in urgent need of improved germplasm. In order to effectively prevent the damage of bacteria and other pathogenic microorganisms on S. broughtonii, we observed the response process of the lysozyme activity in different tissues of S. broughtonii infected by Vibrio anguillarum, and explored the immune function of the lysozyme in the body of S. broughtonii. In this experiment, 20-month-old S. broughtonii. individuals were infected by injecting live bacteria, and 16 individuals were randomly selected. And 1 mL (about 1×109) V. anguillarum suspension was injected into the axe of each individual as the infection group. 16 randomly selected individuals were not injected with V. anguillarum as the control group. The two groups were cultivated in clean seawater for 4、12、24 and 48 h. Each group randomly selected 4 S. broughtonii individuals who were dissected the blood, mantle, gill, axe foot, hepatopancrea and adductor muscle tissues. The concentration of lysozyme was determined by ELISA kit. The results showed that for the invasion of V. anguillarum, the lysozyme content in the blood of the S. broughtonii rapidly increased from the normal low value and maintained a high level, indicating that the blood is one of the main immune tissues of the S. broughtonii body defense pathogen.In the case of no infection, the S. broughtonii mantle always maintained a high lysozyme concentration to prevent the interference of the external water environment. The concentration of lysozyme in infected gills and axe foot are significantly higher than the normal values after the injection about 24 hours, indicating that the mantle, gills and axe foot were the first barrier as the S. broughtonii body to contact with the outside world can also respond to the invasion of pathogenic bacteria, but the response was delayed compared with the blood. The lysozyme content of hepatopancrea and adductor muscle did not change significantly. And it was speculated that hepatopancrea and adductor muscle were not important immune tissues or organs of S. broughtonii. The results of this study can provide relevant parameters for the study of disease resistance and immune mechanism of S. broughtonii.
The role of the Hyriopsis cumingii shell silk-like matrix protein silkmaxin in the shell and pearl biomineralization
Zhonghui XIA, Xiaojun LIU, Jiale LI
Accepted Manuscript  doi: 10.1964/jfc.20181111542
[Abstract](1068) [FullText HTML](550) [PDF 1590KB](12)
Abstract:
Shell matrix proteins control the nuleation、size and crystal phase of calcium carbonate during the biomineralization of pearl, and they are related to pearl quality. In order to study more about the molecular mechanism of nacre formation, we cloned a novel shell matrix protein silkmaxin (accession No. MK188932) from freshwater mussel Hyriopsis cumingii. With the gene expression detected by RT-PCR and in situ hybridization, silkmaxin specially expressed in the pallial epithelial cells of mantle outer fold, which indicated that silkmaxin is a nacreous layer matrix protein. The amino acid sequence of silkmaxin featured high proportion of Gly (33.0%) and Ser (10.4%) residues, and the second structure is mainly composed of β-folds. The high structure prediction indicated that silkmaxin is a silk-like protein. In addition, the expression of silkmaxin was detected in the early stage of pearl formation by real-time quantitative PCR. The results indicated that silkmaxin play important roles in the transition of the calcium carbonate disordered deposition to ordered deposition in the early stage of pearl formation. The study of shell by silkmaxin RNAi treatment indicates that silkmaxin is essential for the correct growth of aragonite tablets, including the size and shape of the newly formed calcium carbonate crystals.
Effect of inorganic carbon source on nitrogen reduction and sedimentation performance of bioflocs
Jingwei GOU, Xiaoning WANG, Hongchun DU, Jieyu CHEN, Xugang HE
In Press  doi: 10.11964/jfc.20190411719
[Abstract](1123) [FullText HTML](571) [PDF 1030KB](6)
Abstract:
The ectopic biofloc reactor was used to compare the simulated carbon sources (NaHCO3) concentration of 0.0 g/L (control group), 0.5 g/L, 1.0 g/L and 1.5 g/L of simulated aquaculture wastewater which effect the nitrogen reduction and sedimentation performance of the bioflocs in two stages: organic carbon source exist (stage I for 21 d) and organic carbon source loss (stage II for 21 d). The results showed that the effluent ammonia nitrogen concentration in the first-stage control group was significantly higher than that in the other treatment groups (P<0.05), but generally decreased first and then stabilized. The nitrite nitrogen and nitrate nitrogen in each group accumulated a small amount; the biofloc biomass and sedimentation rate of the control group were significantly lower than the treatment groups (P<0.05), and the difference between the treatment groups was not significant. There was no significant difference in the concentration of ammonia nitrogen and nitrite nitrogen in the effluent of each group in stage II (P>0.05). The concentration of nitrate nitrogen in the control group was higher than that in treatment groups, and the concentration of ammonia nitrogen decreased rapidly. At this stage, the biomass and sedimentation rate of the bioflocs decreased, and the 1.0 g/L NaHCO3 treatment group showed better sedimentation effect; the particle size distribution also tends to be uniform. During the whole experimental period, the removal efficiency of ammonia nitrogen reached 97.8% and the nitrite nitrogen did not accumulate significantly under different concentrations of inorganic carbon source. The sedimentation rate and biomass of bioflocs in the treatment groups were significantly higher than those in the control group (P<0.05). The results show that the addition of inorganic carbon source can improve the nitrogen reduction performance of bioflocs and enhance its sedimentation rate. After removing the organic carbon source, the biofloc reactor can maintain the ammonia nitrogen removal capacity, but caused nitrate nitrogen accumulation, biofloc organisms. The amount is reduced when the organic carbon source was missing, the inorganic carbon source (≥0.5 g/L) helps the biofloc reactor to maintain its ammonia nitrogen removal capacity.
Effects of different animal baits on the gonad development of YY super-male yellow catfish
Yang XIONG, Shuai WANG, Wenjie GUO, Jiang XU, Lihui CHEN, Hanqin LIU, Jie MEI
In Press  doi: 10.11964/jfc.20190311696
[Abstract](1118) [FullText HTML](567) [PDF 878KB](9)
Abstract:
The emergence of novel variety " All-male NO.1” dramatically promoted the development of the yellow catfish industry, of which the cultivation of YY super-male was a critical step. Recently, YY super-male yellow catfish with intersexual gonad emerged largely, which hindered the development of yellow catfish industry. We only found the problem of gonad development in YY super-male breeding with tubificidae by checking the production and breeding records for nearly 10 years. Therefore, four different baits including Artemia salina, Zooplankton, Chironomus plumosus, Tubificidae were used to treat YY super-male for 20 days (11 to 30 days post hatching). The survival rate, body length, and body weight of each group were measured at 60 dph (day post-hatching). Tubificidae treatments significantly increased the body length and weight compared with other baits, and the survival rate of fish fed with Artemia salina was significantly lower than fish fed with the other three baits. In addition, we performed histology analysis on gonadal structure at 60 dph and 1 year old and statistics of fertilization rate at 1 year old. As a result, the fish group fed with Tubificidae displayed 75% intersexual gonad and 25% testis without seminiferous lobule, and the fertilization rate was only 36.70%±4.05%, which was significantly lower than the other groups. In order to study the reasons for the feminization of YY yellow catfish, we measured the estradiol content and found that the estradiol content was low in all four different animal baits. It is speculated that the feminization of YY super-male yellow catfish may be caused by the environmental endocrine disruptors (EDCS) enriched by Tubificidae. Therefore, zooplankton or Chironomus plumosus could be fed in the early stage of large-scale breeding of YY-supermale yellow catfish, whereas Tubificidae should not be fed.
Effect of south-north relay mode on the nutritive compositions of haliotis discus hannai
Liting ZENG, Shiyi ZHONG, Wweiwei YOU, Ccaihuang KE
Accepted Manuscript  doi: 10.11964/jfc.20181011475
[Abstract](1215) [FullText HTML](609) [PDF 556KB](6)
Abstract:
The south-north relay mode of abalone culture, a common practice in China, was designed to increase the survival rate of abalone in the south in summer. The abalone usually was transported to the north(Rongcheng, Shandong) in April from southern China(Lianjiang, Fujian)and returned to the south in November. In this study, the impact of this mode on the nutritive compositions of abalone (Haliotis discus hannai) were investigated.The main method was the series of GB.5009. The determined indexes include moisture, cholesterol, ash, protein, lipid, glycogen, collagen, mineral elements(Mg、Al、Ca、Mn、Fe、Cu、Zn、Se),delicious amino acids(aspartic acid、glutamic acid、glycine、alanine、arginine、methionine、lysine),taurine and fatty acid. SPSS 24.0 statistical software(independent sample t-test)was used to determine the significance of the differences between two groups. The experimental results were expressed as mean ± standard deviation (X±SD).Two groups of adult abalone(two years old)with the same algae diet (Gracilaria lemaneiformis) were sampled for the analysis in December, 2017. One group was cultured in Lianjiang, Fujian (Southern China) without migration (LJ-DD) and another was moved to Shandong (Northern China) before the summer and returned to Lianjiang in November (SD-DD). Live samples were moved to laboratory within 24 hours, taking abalone foot muscle to freeze drying after anatomy and grinding into powder. These powder were saved in −80 °C freezer.The results showed that contents of ash and collagen were higher in LJ-DD, but not significantly. The cholesterol, lipid and glycogen content were higher in SD-DD, but not significantly. Moisture content was significantly higher in SD-DD (76.50%WW) than LJ-DD(73.70%WW) while total protein content was significantly lower in SD-DD(48.40%DW). For mineral profile, Se content was significantly higher in LJ-DD(0.07 mg/100g)than SD-DD(0.05 mg/100g). Besides, Mg and Al contents were higher in SD-DD and Ca、Fe、Cu and Zn contents were lower in SD-DD, but the differences were not significantly. For amino acid profile, the contents of glutamic acid, arginine, lysine and total delicious amino acid were significantly higher in LJ-DD than SD-DD. Besides, taurine content was significantly lower in SD-DD than LJ-DD. For fatty acid profile, C20:3n6 content was significantly higher in LJ-DD than SD-DD. SFA and N-3 fatty acid were higher in SD-DD, MUFA、PUFA and EPA+DHA contents were higher in LJ-DD, but not significantly. The value of N6/N3 was lower in SD-DD than LJ-DD, but the differences were not significantly. Overall, two groups had similar composition, but SD-DD had higher nutritional value than LJ-DD.To summarize, the south-north relay mode has both some negative influences and some positive influences on the nutritional quality of Haliotis discus hannai, but such difference is not too large in total.
Analysis of the effect of adding Bacillus on the physicochemical factors and bacterial community structure in ponds
Yang LU, Ermeng YU, Jun XIE, Guangjun WANG, Kai ZHANG, Deguang YU, Zhifei LI
Accepted Manuscript  doi: 10.11964/jfc.20181111520
[Abstract](1222) [FullText HTML](616) [PDF 854KB](11)
Abstract:
In order to study the effect of adding Bacillus in the pond on the physicochemical factors and bacterial community structure, high throughput sequencing technology was used to analyze the bacterial community structure in water and sediment of the experimental group (adding Bacillus in pond) and the control group (without adding in pond). At the same time, the physicochemical parameters in water and sediment of the two groups were collected. The results indicated that the contents of TN, \begin{document}${\rm{NH}}_4^ + $\end{document}-N, NO3—N in water were significantly lower than those of the control group (P<0.05), but the contents of \begin{document}${\rm{NO}}_3^ - $\end{document}-N, \begin{document}${\rm{NH}}_4^ + $\end{document}-N, TN and TP in sediment were significantly higher than those of the control group (P<0.05). The abundance of Chlamydomonas debaryana, Zymomonas, Roseomonas, Dechloromonas and Chitinophaga in water of the experimental group was significantly higher than that in the control group (P<0.05). Among of these bacterial communities, Chlamydomonas debaryana have the function of removing \begin{document}${\rm{NH}}_4^ + $\end{document}-N, Dechloromonas and Chitinophaga have the function of removing \begin{document}${\rm{NO}}_3^ - $\end{document}-N, Zymomonas and Roseomonas have the function of denitrification. The Chao1 and Shannon index in water of the experimental group were significantly higher than those in the control group (P<0.05). Hydrogenophaga, Geothermobacter and Haliscomenobacter were negatively correlated with \begin{document}${\rm{NO}}_3^ - $\end{document}-N and TP, and positively correlated with \begin{document}${\rm{NH}}_4^ + $\end{document}-N and TN. Above all, these results showed that adding Bacillus to the pond would lead to the variations of bacterial community structure, thus realizing the regulation of physicochemical factors in the pond. And the results are meaningful for reducing the pollution of aquaculture tail water and water environment.
Study on the relationship between the recruitment of the Pacific-cohort of chub mackerel (Scomber japonicus) and the influence factors on the spawning ground based on GLM and GAM
Shengnan WU, Xinjun CHEN
Accepted Manuscript  doi: 10.11964/jfc.20180811426
[Abstract](1166) [FullText HTML](601) [PDF 738KB](8)
Abstract:
Chub mackerel (Scomber japonicus) is an important pelagic fishes in the Northwest Pacific Ocean. It is necessary for us to find the relationship between the abundance and influence factors, which are beneficial to exploit and utilize this resource. In this study, based on the recruitment data and the spawning stock biomass (SSB) data of the Pacific-cohort of S.japonicus during 1980−2016 obtained from Japan fisheries institution, the normality test of natural logarithm of recruitment was finished and the time period passed the normality test was during 1980−1999, as well as the environmental data of spawning ground, we analyzed the relationship between the sea surface height (SSH), sea surface salinity (SSS), sea surface temperature (SST) and the natural logarithm of SSB (ln(SSB)) and the recruitment during 1980−1999 with generalized linear model (GLM) and generalized additive model (GAM). The GLM results revealed the importance of variables ranked by decreasing magnitude are ln(SSB) ×Year, ln(SSB), SSS ×Year and SSS, which were significant (P<0.05) and considered the combined effects of factors. Considering the single factor in GLM models affected on the recruitment, the importance of variables ranked by decreasing magnitude are SST, SSS, Year, ln(SSB) and SSS. The GAM results indicated that the model which contained Year, SST and SSH was the optimal model based on Akaike’s Information Criterion (AIC), the importance ranked by decreasing magnitude are Year, SST and SSH. However, considering the single factor in GAM models affected on the recruitment, the importance of variables ranked by decreasing magnitude are Year, SSS, ln(SSB), SST and SSH. The suitable range of SSH was 62−65 cm, the suitable range of SSS were 34.72−34.74 psu and 34.78−34.83 psu and the suitable range of SST was 20.2−20.6 °C. When ln(SSB)>6.0, the recruitment was at a high level, based on GAM analysis.
Isolation and identification of hepatocellular exosomes and there effects on the expression of miR-122/33 and immune-related genes in grass carp(Ctenopharyngodon idella)
Ronghua LU, Wenya ZHANG, Yuru ZHANG, Liping YANG, Junli WANG, Xiaolin MENG, Guoxing NIE
Accepted Manuscript  doi: 10.11964/jfc.201211575
[Abstract](1153) [FullText HTML](604) [PDF 944KB](8)
Abstract:
Exosomes are nano-scale vesicles with a phospholipid bimolecular membrane, which can participate in many physiological processes. The aim of this study was to investigate the isolation and identification methods of extracellular exosomes from grass carp hepatocyte and preliminary study on the effects of exosomes secreted from fatty hepatocyte on the expression of miRNAs and immune-related genes in grass carp hepatocytes. In this study, The exosomes of grass carp hepatocytes L8824 were extracted by ultracentrifugation. The morphology of exosomes were observed by Electron Microscopy, the parcicle size and quantity of exosomes were determined by Nano-particle Tracking Analysis. Meanwhile, we analyzed the expression of the specific protein CD63 using Western blot. Then, we used exosomes,which secreted from normal hepatocytes and fatty hepatocyte induced by oleic acid to incubate grass carp hepatocytes, and the effects of two different exosomes on the transcription levels of miR-122/33 and immune-related genes, which are TNF-α, NF-κB, IL-1β, IL-6 and IL-10 were detected by real-time qPCR. Our results indicate that the exosomes secretion of grass carp hepatocytes culture medium are uneven vesicles of 30-150 nm, which was round or oval, and had a complete membrane structure. The expression of exosomes marker protein CD63 was positive, and the NTA results showed that the exosome vesicles accounted for more than 50 % of all the vesicles. Additionally, the exosomes of fatty liver cells significantly increased the expression of miR-122 and the immunogenic genes (TNF-α, IL-1β and IL-6) in hepatocytes (P<0.05). These results suggest that the exosomes of grass carp hepatocytes can be isolated successfully by ultracentrifugation. Moreover, exosomes may play an key role in the regulation of immunity of grass carp hepatocytes.
Dietary vitamin B6 requirement of juvenile sea cucumber Apostichopus japonicus Selenka
Baoshan Li, Jiying Wang, Chengqiang Wang, Tiantian Hao, Shixin Wang, Bingshan Huang
Accepted Manuscript  doi: 10.11964/jfc.20180911449
[Abstract](1381) [FullText HTML](609) [PDF 727KB](6)
Abstract:
The present trial was conducted to investigate the dietary vitamin B6 requirement of sea cucumber Apostichopus japonicas Selenka juveniles. The experimental diets were formulated with graded levels of vitamin B6 (1.23, 5.29, 9.35, 17.47, 33.71, 66.17 mg/kg), and named D1, D2, D3, D4, D5 and D6 group. Each diet was randomly assigned with triplicate sea cucumber juvenile with initial body weight 12.23 g for 12 weeks. The results showed that weight gain rate and specific growth rate presented an increasing firstly and then decreasing afterwards, and got maximum in D5 (33.73 mg/kg) group. Crude protein of body wall was increased firstly by dietary vitamin B6 and then decreased, and crude protein of D6 group was significantly lower than other groups; Crude lipid of D1 group was significantly lower than other groups. All of activities of glucose 6-phosphatede hydrogenase, isocitrate dehydrogenase, acetyl coA carboxylase, and nitric oxide synthesis were increased firstly and then decreased afterwards, activity of D6 group was significantly lower than other groups. With the increasing of dietary vitamin B6, both protease and amylase were increased, and cellulase was decreased by dietary vitamin B6, while the height of villus; MC and the thickness of muscularis were increased significantly. With the weight gain rate as the evaluation indictor, regression analysis showed that the optimum dietary vitamin B6 for sea cucumber juveniles were 45 mg/kg.
Detection of Pacific Saury Fishing Boats in the Northwest Pacific Using Satellite Nighttime Image
Hao TIAN, Yang LIU, Yongjun TIAN, Shigang LIU, Luxin YAN, Guanyu CHEN, Jianchao LI, Yuan LI, Longshan LIN
Accepted Manuscript  doi: 10.11964/jfc.20181011507
[Abstract](1169) [FullText HTML](607) [PDF 1360KB](9)
Abstract:
Pacific saury (Cololabis saira) is one of the most important commercial pelagic fish species being harvested in the northwestern Pacific Ocean region. Spatial and temporal dynamic monitoring of fishing boats has become an important data source for understanding the distributional dynamics of fisheries. Visible infrared imaging radiometer suite (VIIRS) Day/night band (DNB) night-time remote sensing images can be used to monitor night fishing boat lights. In this study spike detection and threshold segmentation techniques were used to identify fishing boats employing DNB images in the Northwest Pacific. GIS tools were used to extract and analyze the fishing boat position and numbers. The fishing log of Pacific saury resource and the selected NPFC fishing boats list were used to validate the identified results. The results show that the method proposed in this study can effectively identify the location and operation status of Pacific saury fishing boats, and provide useful information for understanding the spatial distribution and dynamics of Pacific saury fishing zone in the northwest Pacific region. Sea surface temperature data provided by the National Oceanic and Atmospheric Administration (NOAA) were used to analysis temperature changes in the fishing ground of Pacific saury. The results showed that the SST range of lighting fishing boats changes with the migration of saury. From July to September 2016, the range of fishing ground SST fluctuated largely because Pacific saury are widely distributed, making extensive migrations from subtropical to subarctic regions throughout the Kuroshio-Oyashio currents transition zone. After September, the SST of the fishing ground tended to be stable. In the future, this information could be used to forecast the potential fishing zone and to assess the fishing resources.
Study on the structure and properties of HDPE/ starch composites for fishing
Fei YANG, MIN ZHANG, Jiangao SHI, Wenwen YU, , Wenbo ZHOU
Accepted Manuscript  doi: 10.11964/jfc.20181011503
[Abstract](1141) [FullText HTML](598) [PDF 966KB](3)
Abstract:
The high density polyethylene (HDPE)/starch composites were prepared by melt-spinning. The effect of starch contents on the rheological properties, structure, thermal properties, mechanical properties and dynamic mechanical properties of HDPE/starch composites was studied. The results showed that the introduction of starch improved the rheology and toughness of the composites. When the content of starch was 20 wt%, it was uniformly dispersed at micron -scale thickness in HDPE/ starch composites. When the content of starch increased to 30 wt% and 50 wt%, the starch exhibited spherical dispersed phase in HDPE/starch composites, and the average diameter of starch increased from 0.6 μm to 0.8 μm. The breaking strength and breaking elongation of HDPE/ starch blends decreased significantly with the increase of starch content. All the blends with different starch contents were detected to three transition peaks. The γ transition of HDPE at low temperature corresponds to the glass transition peak of polyethylene, it was related to the movement of the amorphous chain segment, and the content of starch had little effect on the γ transition. The β transition was related to starch phase, there was no β transition for pure HDPE, and the peak became wider with the increase of starch content. The α transition in high temperature zone was related to the movement of the restricted chain near the crystallization zone of polyethylene, it was a complex multiple relaxation process. Introducing a certain content of starch can effectively enhance the rheology and toughness of the composites, this result can provide a theoretical and technical basis for the high- performance fishing materials based on degradable starch.
Identification of MyD88-4 in Mytilus coruscus and expression changes in response to Vibrio chagasii challenge
Xiao LIANG, Yuzhu LIU, Ke CHEN, Yifeng LI, Jinlong YANG
Accepted Manuscript  doi: 10.11964/jfc.20190111611
[Abstract](1186) [FullText HTML](625) [PDF 1337KB](4)
Abstract:
Myeloid differentiation factor 88 (MyD88) is a crucial adaptor protein in the toll-like receptor (TLR) signaling pathway and plays an important role in signal transmission. In this study, the full-length cDNA sequence of a MyD88 gene from Mytilus coruscus (McMyD88-4) was cloned. Its cDNA sequence is 3 930 bp, with a 2 607 bp open reading frame encoding a protein of 868 amino acids. Amino acids at position of 13-109 are the dead domain, and amino acids at position of 347-481 are the Toll/interleukin-1 receptor (TIR) domain, which contains three highly conserved regions Box 1, Box 2 and Box3. The three-dimensional structure of McMyD88-4 contains six α-helix and four β-sheets. According to the comparison with known MyD88 amino acids sequence, the putative protein of McMyD88-4 was most similar to that of Crassostrea gigas, with the identity and similarity of 60% and 77% respectively. Then it was more similar to Patinopecten yessoensis, Argopecten irradians, Ruditapes philippinarum, with 40%-51% of identity and 58%-67% of similarity. Phylogenetic tree showed that McMyD88-4 of M. coruscus firstly clustered with Pacific oysters and scallops, and then with Drosophila, while vertebrates formed a separate cluster. qRT-PCR revealed that McMyD88-4 was expressed in all tissues and organs examined. The highest expression was found in the mantle and gill, while the lowest expression found in haemocytes. After infection by Vibrio chagasii, the expression of McMyD88-4 was up-regulated sharply in immune-related tissues, and reached the peak at 3 h and 6 h, and the up-regulation level in digestive gland was significantly higher than that in gill and mantle. The present results showed that McMyD88-4 plays an important role during the immune response of M. coruscus against external pathogens, especially Vibrio infections.
A research on the ralationship between lunar phase, water depth and operation time and CPUE of purpleback flying squid (Sthenoteuthis oualaniensis) in South China Sea in spring
Chunxu ZHAO, Xingyu QIU, Xiongbo HE, Guoyi WANG, Yinna GU, Yana ZHONG, Yunrong YAN, Bin KANG
Accepted Manuscript  doi: 10.11964/jfc.20181111552
[Abstract](1225) [FullText HTML](608) [PDF 1121KB](7)
Abstract:
According to the yield data of the purpleback flying squid in the southern and northern sea area of the South China Sea in spring in 2015 and 2016, the present research was carried out to analyze the relationship between depth, working time and moon phases and CPUE under the condition of operating. From the GAM model analysis, we knew that the effect of operation time and lunar day on CPUE was significant (P < 0.01). The results showed that CPUE is relatively low at the depth of 0-999 m under the water in the bright moonlight. When there was no-moonlight, the CPUE in each water layer changed little, and the CPUE at the depth of 2500-2999 m was relatively higher. When the working time in the first half of the night (21:00~24:00), the CPUE was higher, which wan up to 399.4 kg/net the most, and the CPUE gradually decreased in the second half of the night (0:00~5:00). There was a great difference in the yield of the bright moonlight and no-moonlight, which were respectively 267.0 kg/net and 321.6 kg/net. El nino has impact on the changes of the purpleback flying squid resources in various water layers to a certain extent. The research on the effect of operational conditions on CPUE of the purpleback flying squid can provide reliable suggestions for fishing ground.
Molecular evolution analysis of interleukin-8 in great blue-spotted mudskipper (Boleophthalmus pectinirostris) and the effect of different pathogen stimulus on its expression
Jian LI, Fanxing MENG, Ming LI, Rixin WANG, Ge SHI
Accepted Manuscript  doi: 10.11964/jfc.20181111545
[Abstract](1234) [FullText HTML](687) [PDF 1910KB](5)
Abstract:
Great blue-spotted mudskippers (Boleophthalmus pectinirostris) have lived in mudflats off the coasts of Japan and south of China for a long time. Compared with the fish living in water, B. pectinirostris, as an amphibious fish, is more vulnerable to terrestrial and aquatic pathogenic factors. Interleukin-8 is a CXC chemokine that plays an important role in regulating the inflammatory response. In this study, we screened the interleukin-8 gene from skin transcriptome of B. pectinirostris, then cloned and verified its coding region. The results indicated that the open reading frame(ORF) of B. pectinirostris IL-8 gene was 306 bp, coding 101 amino acids, including a typical signal peptide of 18 amino acids, and a SCY domain of 62 amino acids, which also possessed the four conserved cysteine residues, namely Cys-30, Cys-32, Cys-57 and Cys-73. Like most fish, B. pectinirostris interleukin-8 amino acid sequence lacked the ELR motif which was the receptor binding site and it was replaced by Asn-Ser-His (NSH) in great blue-spotted mudskipper. In all known fish amino acid sequence, rules of this motif were as follows: the first amino acid was never the amino acid with positive charge, the second amino acid was general those amino acids with no charge, and most of third amino acid were amino acids with positive charge. Phylogenetic analysis showed that purification selection affected the diversity of this motif in fish. Tissue expression analysis by RT-qPCR indicated that interleukin-8 gene was widely expressed in healthy tissues of B. pectinirostris and it had the highest expression in the gill and brain. Bacteria and poly (I∶C) injection experiments showed that expression of IL-8 in liver, spleen and brain tissues was up-regulated after the infection, indicating that IL-8 plays an important role in the inflammatory response and immune response of liver, spleen and brain tissues. This study provided important reference for the research of immune genes of B. pectinirostris, thus having a more comprehensive understanding of the evolution process and function of fish immune genes.
Transcriptional expression and prokaryotic expression analysis of haloalkane dehalogenase gene from Gracilariopsis lemaneiformis
Peng SUN, Yu DU, Yan LÜ, Xue SUN, Nianjun XU
Accepted Manuscript  doi: 10.11964/jfc.20180611324
[Abstract](2584) [FullText HTML](1249) [PDF 1069KB](12)
Abstract:
Haloalkane dehalogenase (HLD) is a kind of enzyme that can degrade halogenated aliphatic compounds. In order to provide information on the possible use of the algal HLD for the degradation of halogen compounds in the environment, we used bioinformatics, quantitative real-time PCR and pET28a system to study the characteristics and prokaryotic expression of HLD in the macroalga Gracilariopsis lemaneiformis (Rhodophyta). The open reading frame of HLD in G. lemaneiformis (recorded as GlHLD) is 969 bp, and its theoretical molecular weight and isoelectric point is approximately 36.33 ku and 5.53, respectively. The GlHLD amino acid sequence is identical to an HLD sequence of G. chorda (PXF45553.1), and is close to G. chorda and Chondrus crispus in the phylogenetic tree. The high temperature, substrate 1,2-dichloroethane and phytohormone salicylic acid all promoted the expression of GlHLD gene with an increment fold of 3.64, 2.64 and 2.43 times, respectively. Finally, the recombinant vector of pET28a-GlHLD was transformed into E. coli BL21 (DE3), and the recombinant protein displayed a dehalogenase activity. The optimal induction conditions were 16 °C and 0.1 mmol/L IPTG treatment for 12 h. And then, the HLD protein was preliminarily purified by nickel column. This study will lay the foundation for further understanding of the algal HLD family and the acquisition of high purity HLD enzyme.
Isolation, identification and pathogenicity studies on visceral granulomatous disease in Acanthopagrus schlegelii
Honghu ZHANG, Na YUAN, Chaoying FU, Jie HE, Huaming LUO, Jiawei BAO, Dong QIAN
Accepted Manuscript  doi: 10.11964/jfc.20181011489
[Abstract](2039) [FullText HTML](662) [PDF 1307KB](8)
Abstract:
A serious disease occurred in black seabream, Acanthopagrus schlegelii, cultivated in runway fish culture pond of mariculture farm in Taizhou, Zhejiang province, in April, 2017. The diseased fish showed sluggish swimming, anorexia and ulceration on surface. Moribund fish were dissected with symptom of massive ascites and swelling on liver, spleen and kidney, with white granulomatous nodules, especially in spleen. The bacteria were isolated with tryptone soybean agar, and all the fish with typical symptoms showed the pure culture of grayish white colony with Gram negative rods. The bacterial strain AS15, from the spleen of fish with most serious granulomatous, was choose for challenging test to healthy black seabream by injection intraperitoneally. Mortality was recorded with similar symptom with native infected seabream, with the median death dose of 6.5×104 CFU/ind. AS15 was identified as Edwardsiella tarda with API 20E biochemical bacteria identification system as well as 16S rDNA sequences blasted on NCBI, with 99% similarity to reference strains. With phylogenetic analysis for 16S rDNA, AS15 belonged to the same cluster with ETT883、LADL05-105, E. piscicida according to new classification for genus E.dsiella, and same cluster to LADL05-105 and NCIM2056, E. piscicida-like, the new recommended species of the genus, with 100% similarity on gyrB phylogenetic tree. The species-specific primers for genus E. dsiella were used for PCR test, and AS15 showed positive to EPL, the species primer for E. piscicida-like, and PCR negative to all other three primers of E. tarda, E. piscicida and E. ictalur. Ten pathogenic gene, including four fimbrial genes, and sodBcitCesrBmukFkatB, the related virulence gene were analyzed by PCR. The strain AS15 showed positive to all four fimbrial genes and other virulence gene except gene gadB. It could be considered that AS15, E. piscicida-like bacteria, the first pathogenic strain isolated and reported from marine cultivated seabream, was the pathogen of serious outbreak case of visceral granulomatous disease in black seabream in runway pond culture system.
Comparison effect of taurine on acute ammonia toxicity in genes involved in antioxidant and inflammation of Carassius auratus and Ctenopharynodon idellus
Qian ZHANG, Muzi ZHANG, Ming LI, Rixin WANG
Accepted Manuscript  doi: 10.11964/jfc.20181011469
[Abstract](1241) [FullText HTML](624) [PDF 1380KB](7)
Abstract:
The four experimental groups were carried out to test the response of Carassius auratus and Ctenopharynodon idellus to ammonia toxicity and taurine within 96 h: group 1 was injected with NaCl, group 2 was injected with ammonium acetate (C. auratus: 7 mmol/g; C. idellus: 9 mmol/g), group 3 was injected with ammonium acetate and taurine (100 μg/g), and group 4 was injected with taurine. C. auratus in group 2 had lower mRNA expression of SOD, CuZnSOD and CAT in liver than those of fish in groups 1 and 3; fish in groups 2 and 3 had lower mRNA expression of GPX in liver than that of fish in group 1; the highest mRNA expression of SOD, CuZnSOD, CAT and GPX in brain were found in group 1; C. idellus in groups 2 had higher mRNA expression of SOD, CuZnSOD, CAT and GPX in liver; fish in groups 2 and 4 had lower mRNA expression of SOD and CuZnSOD in brain than those of fish in groups 1 and 3; fish in group 3 had the highest mRNA expression of CAT and GPX in brain. C. auratus and C. idellus in group 2 had the highest mRNA expression of TNF and IL in the brain and liver. This study indicates that defensive strategies are more effective on grass carp in dealing with the ammonia challenge compared with crucian carp; the taurine could more effective mitigate the adverse effect of oxidative stress on C. auratus and C. idellus, but the inflammatory response in hyperammonemia C. auratus and C. idellus were not affected by taurine.
Effect of unfrozen liquid treatment on the quality and shelf life of grouper in normal temperature direct-sale logistics course
Yanyan WU, Tao ZHANG, Laihao LI, Xianqing YANG, Shuxian HAO, Wanling LIN
Accepted Manuscript  doi: 10.11964/jfc.20181011509
[Abstract](1210) [FullText HTML](633) [PDF 1107KB](2)
Abstract:
In order to understand the quality change and shelf life of high quality cultured grouper(♀Epinephelus fuscoguttatus×♂E. lanceolatue) after the treatment of unfrozen liquid in the normal temperature direct-sale logistics course, in this paper, the fresh grouper was treated with unfrozen liquid, and its muscle microstructure, the change of temperature curve, sensory evaluation, total volatile basic nitrogen (TVB-N), the total number of colonies and K value were determined, and compared with the results of air freezing treatment and control group. The results showed that the treatment of fresh grouper with unfrozen liquid not only can maintain the quality of fresh fish, but also can extend the shelf life of normal temperature logistics, and the logistics time can reach 80 h. At this time, its TVB-N reached 26.88 mg/100 g. The K value was 47.965%, the colony number was 5.88 lg (CFU/g), the fish muscle fiber structure was intact, close to fresh fish meat, and the sensory evaluation was good, which was 10 hours longer than the still air freezing group and 30 hours longer than control group. This research can provide new fresh-keeping, fidelity and quality assurance technology for high-quality groupers, and also provide technical support for the current grouper’s normal temperature logistics demand from the direct production of the grouper to the consumer's home.
Histological and morphological observations of the gill and swim bladder development of Lateolabrax maculatus
Yang LIU, Haishen WEN, Jiesi HUANG, Jifang LI, Meizhao ZHANG, Xin QI, Yun LI
Accepted Manuscript  doi: 10.11964/jfc.20180711362
[Abstract](1263) [FullText HTML](646) [PDF 1478KB](6)
Abstract:
In order to elucidate the development of gill and swim bladder of Lateolabrax maculatus, in this study, histological section technique and morphological observation were used to systematically study the occurrence and development of gill and swim bladder of L. maculatus from 1 to 45 days. The results showed that the post-embryonic development of the gill of L. maculatus juvenile can be divided into four stages, including the appearance period of gills primordium (0-3 d), the differentiation period of filaments (4-14 d), the differentiation stage of lamella (15-25 d) and the completed period of gills (26-45 d). At the water temperature of 15-18 °C, the primordial filament was observed at 1 d, and the lamella structures formed from the pseudobranch were firstly observed at 15 d. After 25 d, the lamella structures were widely distributed in each juvenile gill arch. After 45 d, a well-developed gill structure of juvenile fish was clearly detected and identical to adult fish. According to the observation results, the development stages of the swim bladder organ of L. maculatus were divided into four stages: formation, expansion, aeration and degeneration. The appearance of swim bladder primordium was not observed on the newly hatched larvae, but after hatched for 1 day. After 5 d, the swim bladder cavity of larvae becomes larger and longer. The inflation of the larvae swim bladder was completed at 11 d. Finally, the degeneration of swim bladder of larvae began to occur after 13 d.
Molecular cloning, prokaryotic expression and positioning analysis of C-type lectin 3 (MnLec3) cDNA from oriental river pawn(Macrobrachium nipponense)
Shengming SUN, Hongtuo FU, Fujun XUAN, Xianping GE, Jian ZHU, Xugan WU
In Press  doi: 10.11964/jfc.20180611327
[Abstract](2144) [FullText HTML](1063) [PDF 1222KB](14)
Abstract:
C-type lectins are a large family of proteins that exist in all deuterostomia. C-type lectins can bind to carbohydrate moieties normally in a calcium-dependent manner and play important roles in immune defense. This study aims to explore the expression patterns of C-type lectins gene in different tissues, celluar localization and becteria challenge in Macrobrachium nipponense. The cDNA sequence of M. nipponense (MnLec3) was obtained using rapid amplification of cDNA ends method (RACE) and RT-PCR. The expression levels of MnLec3 in different tissues and different time of artificially challenged with Aeromonas hydrophilia were analyzed by qRT-PCR. The full-length cDNA sequence of MnLec3 was 1 357 bp, which contained a 5′ untranslated region of 125 bp, a 3′ untranslated region of 206 bp, a 1 026 bp open reading frame (ORF) encoding 341 amino acids. The deduced amino acid sequence of MnLec3 had a signal peptide containing 17 amino acid residues and a carbohydrate recognition domain (CRD). Phylogenetic tree analysis stated that oriental river prawn has the closest relationship with other crustacean. The expressed recombinant MnLec3 protein and polyclonal antibody were obtained in present study using a conventional method. Furthermore, immunofluorescent staining technique was used to determine and cellular localization of MnLec3 in hepatopancreas of prawns. Quantitative real-time RT-PCR analysis showed that the MnLec3 gene was expressed in haemocytes, hepatopancreas, muscles, gill, testis, ovary and intestines with the highest level of expression in the hepatopancreas. Real-time PCR analysis indicated that MnLec3 transcripts level showed significant change in hepatopancreas after the prawns was artificially challenged with A. hydrophilia, followed return to control levels at post-injection 96 h, which were similar with MnLec3 protein expression abundance using western blot. The results suggested that MnLec3 might be involved in the immune response against bacterial.
Cloning, expression, antibody preparation and tissue distribution of tilapia lake virus nucleoprotein
Guomao SU, Zhendong QIN, Jiabo LI, Meng ZHOU, Jinfeng MO, Kai ZHANG, Rishen LIANG, Zaohe WU, Lijuan ZHAO, Li LIN
Accepted Manuscript  doi: 10.11964/jfc.20190211657
[Abstract](1519) [FullText HTML](681) [PDF 1571KB](19)
Abstract:
Oreochromis spp. are important cultured fish species worldwide. Recently, tilapia lake virus (TiLV) has been epidemic in many countries and posed a serious threat to Oreochromis spp. aquaculture industry. China has contributed the most amount of cultured Oreochromis spp in the world. Up to date, there is no report of the TiLV epidemic in Oreochromis spp. in the mainland of China. However, since O. niloticus (GIFT strain) is one of the most cultured Oreochromis spp species in the mainland, therefore it is necessary to characterize the features of the GIFT strain infected with TiLV. Taking the advantage of the TiLV was kindly gifted by Dr. Sven Bergmann from Institute of Infectology, Friedrich Loffler Institute, we performed the infection of TiLV in the GIFT strain. The whole nucleotide sequences of the sixth genomic segment of TiLV from the experimental infected O. niloticus were determined. The length of the cDNA of the sixth genomic segment was1 044 bp containing an open reading frame of 954 bp encoding a protein with 317 amino acids with predicted molecular weight of 36.38 ku. There is 5′ end non-coding region of 19 bp and 3′end non-coding region of 972 bp. The sequences and phylogenetic tree analysis showed that the sixth genomic segment encoded TiLV nucleoprotein (NP). Subsequently, GST fusion NP was expressed in Escherichia coli and purified, and it was used to immunize New Zealand white rabbit (Albus lepus) according to the conventional method to prepare rabbit anti-NP polyclonal antibody. The results showed that the antibody titer obtained by ELISA was higher than 1:51 200, and the antibody could specifically recognize the NP protein from the tissues of O. niloticus infected with TiLV. Hematoxylin-eosin staining (H.E) was performed on different tissues of O. niloticus. The results showed that there were apparent pathological changes in the observed tissues, including hepatic necrosis and syncytium; vacuolization, necrosis and increased amount of hemosiderin in the spleen; necrosis and inclusion body in the head kidney; dissociation and shedding of the epithelial cells of the gill filament, small pieces adhered to each other; vacuoles of nerve cells in the brain tissue. Western blot and immunohistochemistry (IHC) were used to detect the expression of the NP protein in different tissues of O. niloticus infected with TiLV. The results showed that the highest amount of NP protein was expressed in the liver, followed by in the brain, trunk kidney and head kidney. In order to elucidate the immune responses of O. niloticus to the TiLV infection, real-time quantitative PCR (qRT-PCR) was used to measure the mRNA expressions of TNF-α and TGF-β in the spleen and head kidney which are the two major immune tissues of fish. The results showed that during the early period of the infection (12-24 h post of the infection), the expression of both TNF-α and TGF-β was significantly inhibited by the viral infection, indicating that TiLV might inhibit these cytokines so as to facilitate its early replication in the host. The current study will shed a new light on the pathogenesis of TiLV infection and will pave a new way on the development of effective prevention and control strategy against the epidemic of TiLV in O. niloticus.
Spatiotemporal heterogeneity of Priacanthus spp. resources in the northern South China Sea
Yuxi LIU, Xuefeng WANG, Guobao CHEN, Shaoliang LÜ, Jiawei ZENG
Accepted Manuscript  doi: 10.11964/jfc.20190111648
[Abstract](1332) [FullText HTML](691) [PDF 1420KB](17)
Abstract:
It’s helpful to know the formation of fishing grounds by the center of gravity of fish resource density and temporal and spatial heterogeneity. The traditional economic fish resources are declining owing to the impact of over fishing, environmental change and other factors. Priacanthus spp., the main catches in bottom trawls in the South China Sea, are important in ecological. But few studies of their spatial-temporal patterns of distribution are available, and spatial autocorrelation of data is often lacking in the studies. Analysis of temporal and spatial heterogeneity in the distribution of Priacanthus spp. in the northern South China Sea has significance for sustainable development and rational management of the fishery. To study this, we used the data of bottom trawl fishery in the northern South China Sea by a fishery information network from 2009 to 2014, for spatial analysis of center of gravity and semivariogram plots to investigate temporal and spatial distribution of Priacanthus spp. resource density. The results showed that the resource density of Priacanthus spp. was a gradually decreasing trend and the differences were extremely significant (P<0.01) from 2009 to 2014. The maximum value of resource density was (26.69±7.34) g/h/kW/nets in 2012. The center of gravity of the resource density distributed between the 50-m and 100-m isobath in the middle part of the survey area, and the differences were not significant (P>0.05). The spatial distribution of Priacanthus spp. in the survey area displayed a well-organized structure, with strong spatial autocorrelation in 70–90 km. Spatial heterogeneity in resource density of Priacanthus spp. appeared to be caused less by randomness than by structural variations. The spatial distribution of Priacanthus spp. displayed weak spatial autocorrelation when the distance exceeded 90 km.
Research of genetic diversity based on the mitochondrial COI gene sequences in four populations of Paramisgurnus dabryanus
Wenrui SHI, Lei WANG, Dongdong Fang, Mengrong Li, Xuejun Li, Junping Chen, Huifen Liu, Chuanju Dong
Accepted Manuscript  doi: 10.11964/jfc.20180911456
[Abstract](1306) [FullText HTML](798) [PDF 754KB](17)
Abstract:
In order to research the genetic diversity of different populations of Paramisgurnus dabryanus, four populations from Liaoning, Henan, Hubei and Taiwan were analyzed by sequencing the mitochondrial cytochrome oxidase subunit Ⅰ(COI) genes. The results showed that 642 base pair(bp)fragment was consisted of A, T, C and G base with 23.5%, 30.6%, 26.7% and 19.2%, respectively, indicating a preference for A and T base. A total of 44 mutations of nucleotide and 23 haplotypes were identified in 4 populations. The haplotype diversity index ranged from 0.424~0.855, and the nucleotide diversity ranged from 0.000 84~0.016 59, the results indicated that Paramisgurnus dabryanus from Taiwan population had a higher genetic diversity than Liaoning, Henan and Hubei population. The genetic differentiation index (Fst) and genetic distance showed that genetic differentiation among Taiwan and other populations was represents extremely significant difference (P<0.01), also had a further genetic distance with other populations. In general, the results showed that there was a certain genetic difference between the different geographical groups, AMOVA analysis revealed that 52.11% of genetic variations derived among populations and 47.89% of genetic variations occured within populations. In terms of the negatively selective neutrality test, the results indicated that a population expansion occurred in the populations of Liaoning, Henan and Hubei population. Which provides a reference for protection of the genetic diversity and breeding work of Paramisgurnus dabryanus.
Behavioral characteristics of large yellow croaker (Larimichthys crocea) in tank by ultrasound pinger system
Wei SONG, Leiming YIN, Xuezhong CHEN, Lei WANG, Yongli LIU, Yongjin WANG, Lingbo MA, Lumin WANG
Accepted Manuscript  doi: 10.11964/jfc.20181211582
[Abstract](1863) [FullText HTML](874) [PDF 827KB](13)
Abstract:
In order to understand the behavioral characteristics of large yellow croaker (Larimichthys crocea), the ultrasound pinger system has been used to track 4 tails test fish for 24 hours to access the fish movement data by implanted methods on Aug. 27th and 28th, 2018. The results show that: ① the vertical movement depths of the text fish is 0.89±0.51 m (18:00—24:00), 0.73±0.50 m (0:00—6:00), 1.04±0.50 m (6:00—12:00), 1.00±0.45 m (12:00—18:00), and keep in 0.5—1.25 m; ②the horizontal movement of test fish appear on the inside of tank about 159±9.50 times, and 27% in total data, and about 489±12.50 times appear around tank, 73% in total data, it means that the fish are assembling inside the tank and do the random motion, occasionally appear motion around the tank wall. This experiment is the first time to study the behavioral characteristics in tank-farming by ultrasound pinger system, it is aims to provide a scientific theoretical basis and data support for the fishing management for production and behavior monitor of L. crocea.
Cloning and tissue expression analysis of the Calcium/ calmodulin dependent protein kinase IV gene (CaMKIV) in Onchidium reevesii
Wei LANG, Tiezhu YANG, Heding SHEN, Guolv XU, Bingning GU, Baobao XUE
Accepted Manuscript  doi: 10.11964/jfc.20180911460
[Abstract](1601) [FullText HTML](813) [PDF 1130KB](21)
Abstract:
Calcium/calmodulin-dependent protein kinase IV (CaMKIV) which has multiple physiological functions in organisms, is a regulatory factor that widely found in eukaryotes. To investigate the role and molecular mechanism of CaMKIV on Onchidium reevesii in the process of evolution from sea to land, and further explain the physiological function of CaMKIV to provides a scientific theoretical basis, a series of experiment was been carried out. In this study, the cDNA sequence of CaMKIV gene was cloned by RACE-PCR using nervous tissue of O. reevesii, and bioinformatics analysis and QRT-PCR experiment were performed. The results suggested that the full-length cDNA of CaMKIV gene consists of 1603 base pair (bp), 315 bp 5' non-coding region (UTR), 256 bp 3' non-coding region (UTR) and 1032 bp open reading frame (ORF) which encode a total of 343 amino acids. The atom of the polypeptide chain encoded by this gene was predicted. The CaMKIV protein was predicted to contain 5 490 atoms, the molecular weight is about 3.873 7 ku, the theoretical isoelectric point is 6.12, the molecular formula is C1741H2768N452O514S15, and the N-terminal signal peptide is composed of 1-29 amino acids. The amino acid sequence alignment and phylogenetic tree results suggest that the CaMKIV gene was closest to the CaMKIV gene of,Aplysia californica and the Biomphalaria glabrata, and its phylogenetic analysis was consistent with the traditional morphological classification. The results of real-time PCR indicated that the CaMKIV gene was expressed in all tissues, and the relative expression in the foot was the highest, followed by the dorsal skin and mouth, and the expression level in the ganglion, albumen gland, intestine, hepatopancreas and other organs were low. It was preliminarily speculated that the gene played an important role in the ganglion of O. reevesii, or it was the molecular basis for the biological body to perceive external environmental variables. The results of this experiment will provide a theoretical support for further understanding of the regulation of the physiological functions of nervous structure and the function of CaMKIV gene, and also provide a reference for exploring the environmental adaptation mechanism of marine animals in the process of evolution from ocean to land.
Study on interaction of autophagosome and microtubule during autophagy process in Cherax quadricarinatus
Fanjuan MENG, Guangcheng ZHANG, Wenjuan YIN, Liyan WANG, Jinsheng SUN
In Press  doi: 10.11964/jfc.20180811406
[Abstract](1961) [FullText HTML](937) [PDF 775KB](9)
Abstract:
Insect research suggests that autophagy plays an important role in virus infection and proliferation, while shrimp autophagy research reports are rare. Understanding the autophagy of shrimp cells will open up new ideas for shrimp disease immunity research. Autophagy related protein LC3 is a marker protein of autophagy, existing in the membrane of autophagosome during the whole autophagy process. Our bioinformatics analysis found that Cherax quadricarinatus LC3 (CqLC3) and α-tubulin (Cqα-tubulin) has the interaction relations. To further reveal transport way of autophagosome during autophagy process, in this study, recombinant plasmids pET-HIS-CqLC3 and pET-GST-Cqα-tubulin were constructed and induced for protein expression in vitro. Then HIS and GST tagged fusion proteins HIS-CqLC3 and GST-Cqα-tubulin were purified by using affinity chromatography respectively. Recombinant proteins HIS-CqLC3 and GST-Cqα-tubulin were found binding each other by the GST pull down assay. In order to further reveal the role of microtubules for autophagosome transport, C. quadricarinatus cell microtubules were depolymerized by vincristine which was one microtubule inhibitor, then the autophagosomes were detected by MDC staining. The results showed that autophagic reaction was incomplete, and autophagosomes increased after microtubule depolymerization. Therefore, the autophagosomes in C. quadricarinatus cells can interact with microtubules through CqLC3, and microtubules play an important role in autophagosome transport during autophagy process. This paper firstly revealed the transport pathway of autophagosomes in shrimp autophagy, and the results laid the foundation for the study of autophagy in shrimp cells.
Target strength measurements of tethered live Purpleback flying squid (Sthenoteuthis oualaniensis) at sea
Huanhuan WANG, Jun ZHANG, Zuozhi CHEN, Yong TANG, Mingshuai SUN, Jiaxing HUANG, Yongsong QIU
Accepted Manuscript  doi: 10.11964/jfc.20180611318
[Abstract](1849) [FullText HTML](883) [PDF 1075KB](8)
Abstract:
Knowledge of target strength (TS, dB) is essential for accurate assessment of fish abundance using acoustic methods. In order to investigate acoustic scattering characteristic of purpleback flying squid Sthenoteuthis oualaniensis, 25 squid specimens were collected by jig in the open sea in the northern South China Sea in September 2017 near geographical position 18°42.9′N 113°05.5′E. The TS of 25 specimens were measured respectively one by one using Simrad EY60 split-beam scientific echosounder with 120 kHz and self-made tethering-controling device. In this paper, we primarily explored the impact of different parameters on the single target detection for Sthenoteuthis oualaniensis, and the parameters included pluse length determination level (PLDL, dB), min normalized pluse length (min NPL), max normalized pluse length (max NPL) and maximum standard deviation of minor-axis angles (MIA). Then we analyzed comprehensively the stochastic nature of single TS which was highly variable, and concluded the mathematical regression relation between TS of S. oualaniensis and mantle length (ML, cm). The results showed: (1) As the PLDL increased, the number of single target of squid detected increased firstly and then decreased, and the number was the largest when PLDL was 6 dB, while the average TS of all single targets increased monotonously. With increase of min NPL, the number of single squid target decreased; in the range of min NPL<0.7, the average TS of all single targets presented increasing obviously. When the max NPL was less than 1.2, the number of single squid target increased as the max NPL increased, but the average TS decreased; when the max NPL fell in between 1.2 and 1.8, the number of single squid target presented increasing slowly, but the average TS remained relatively stable. As the MIA increased, the number of single squid target increased, but the average TS decreased; (2) In this study, the optimum parameters setting of single target detection were as follows: PLDL=6.00 dB, Min NPL=0.7 dB, Max NPL=1.8, MIA=0.8°; (3) The maximum and minimum value of the average single TS of live Sthenoteuthis oualaniensis specimens were respectively -48.6 dB and -63.63 dB, and the corresponding mantle length of Sthenoteuthis oualaniensis were respectively 25.2 cm and 12.4 cm. The mathematical regression relation between TS of Sthenoteuthis oualaniensis and mantle length (ML) were concluded as follows: TS=34.22 Lg ML–98.23 (N=16, R2=0.603). This TS measurement was the first attempt to investigate the investigate acoustic scattering characteristic and TS of live Sthenoteuthis oualaniensis using tethering controlling method at sea by field work. The results of this paper not only accumulated important information and experience for further investigating the acoustic scattering characteristics and improving the acoustic estimation precision of Sthenoteuthis oualaniensis, also provide the reference for measuring TS of other squid or fish by tethering method at sea.
Comparison of the relation between the length frequency distribution and sample size for several commercial fish species in the Wentai fishing ground
Libin DAI, Siquan TIAN, Weicheng LIU, Chunxia GAO, Jiaqi WANG, Xiaoxue DU
In Press  doi: 10.11964/jfc.20170610861
[Abstract](2076) [FullText HTML](960) [PDF 1300KB](14)
Abstract:
Length distribution data provide insight into the dynamics of fish populations. However, it is hard to determine the sample size required to describe size structure. In order to compare the relation between the precision of frequency distributions and sample size for several commercial fish species in the Wentai fishing ground, a resampling approach was used to calculate the mean square difference of length distributions based on actual sampling size and various simulated sampling sizes. The results showed that: ①Factors such as biology difference and seasonal variation would affect the relation of the precision of frequency distributions and sample size. ②The accuracy for estimating the precision of length frequency distributions would be impacted by the numbers of length intervals in iteration calculation. ③The precision of length frequency distributions could be considered as a theoretical basis to optimize sample size. For the reason of lacking domestic researches on sampling design and optimization, the results of this study could provide certain technical reference.
Isolation, identification and phylogenetic analysis of an infectious hematopoietic necrosis virus isolated phylogenetic analyses from Oncorhynchus mykiss at PenZhou city, SiChuan province
Tao LIU, Wenyan WEI, Jiaxing LIU, Ma YANG, Qian YANG, Shengyu HE, Qiyao HE, Heng XIE, Kaiyu WANG
In Press  doi: 10.11964/jfc.20180511284
[Abstract](2362) [FullText HTML](1265) [PDF 979KB](15)
Abstract:
An outbreak of an infectious disease occurred amongst farmed Oncorhynchus mykiss at PenZhou city, Sichuan Province, in October 2017 with heavy mortality of 85%. Major symptoms of the diseased fish included darkening of the body, yellow mucoid fluid fecal casts on anal. Internally, the symptoms were hemorrhage in the swim bladder and peritoneum, gastric distention, enteritis and hydropericardium. Bacteriologic test was negative. Histopathologically, the spleen showed typical coagulative necrosis with marked degeneration and necrosis in the haematopoietic tissue. Hepatocytes showed degeneration and necrosis and edema in some areas. After filtration treatment, the tissue suspension was injected intraperitoneally into 60 O. mykiss. The O. mykiss displayed similar clinical symptoms as fish that were naturally infected. The O. mykiss died acutely in the trial group (cumulative mortality rate of 85%), while there was no abnormal fish in the control group. After filtration treatment, the spleen tissue suspension was inoculated to the Fathead minnow cells (FHM). The typical cytopathic effects were observed after three blind passages in FHM. RT-PCR assay of tissue filtrates from the fish natural infected, the fish artificial infected and diseased cells were IHNV-positive. The amplification products shared 98.2% identity to that of IHNV nucleoprotein gene at nucleotide level. Phylogenetic analysis based on the G gene showed that the viral isolate was classified into Asian isolates, belonged to the JRt genotype.
Management and assessment of spotted mackerel (Scomber australasicus) biomass in the Pacific Ocean
Chang ZHANG, Xinjun CHEN
In Press  doi: 10.11964/jfc.20171211117
[Abstract](2375) [FullText HTML](1395) [PDF 995KB](19)
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Spotted mackerel (Scomber australasicus) is an important economic species in northwest Pacific. The paper evaluates the Pacific stock biomass by aged-structure Virtual Population Analysis (VPA) and Yield per recruit model, and analyses the utilization of stock biomass by using the mackerel catch and CPUE data of the Pacific group which is supplied by Japan's central fisheries research institute from 1995 to 2015. The results show that the biomass of spotted mackerel remains at a high level. The stock biomass is about 650000 tons in 2015, the average fishing mortality shows a trend of falling volatility and fishing mortality of 2015 is 0.15, the current fishing mortality (Fcur) is 0.33, the spawning potential ratio (SPR) remains 36.5%. There is no growth overfishing and recruitment overfishing. It is also discussed that the fluctuations of natural mortality caused by water temperature change and different fishing age affect the resources of spotted mackerel. The study suggests that the fishery is currently utilized in the sustainable way and has great potential for development. It also suggests that the fishery resource could be developed and utilized by using the management reference point F0.1.
The study on the growth, digestive enzymes and immune enzymes activities in the two growth status of seahorse Hippocampus erectus
Yongchun HUANG, Chenling TU, Hongyi Weng, Xiangri LING
In Press  doi: 10.11964/jfc.20171010988
[Abstract](2355) [FullText HTML](1279) [PDF 665KB](8)
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The paper studied the occurrence time and physiological characteristics of slow growth seahorse. Comparisons of the growth, the ratio of RNA/DNA, digestive enzymes and related immune enzymes activities in normal growth seahorses[(8.57±0.61) cm, (1.51±0.38) g] and slow growth seahorse [(6.68±0.35) cm, (0.81±0.14) g]Hippocampus erectuswere studied in a cultural experiment for 110 d. The results showed that the average daily gain, specific growth rate, condition factor and viscera index in the normal growth seahorses were significantly higher than those of the slow growth seahorse, respectively. The normal growth seahorses grew faster than that of the slow growth seahorses after the body length was5.026 cm. The amylase, protease and lipase activities in normal growth seahorses were as the same tendency as those of the slow growth seahorses under different reaction temperatures (5 °C, 15 °C, 25 °C, 30 °C, 35 °C, 45 °C and 55 °C) and pH (2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 and 9.0). However, the digestive enzymes activities of the former were higher than those of the latter, except amylase activity at 35-55 °C and protease activity at 5–25 °C. The activities of ACP、AKP、T-AOC and SOD in normal growth seahorses were 12.83%, 48.21%, 44.71%and 65.75% more than those of the slow growth seahorses, respectively. The MDA of the normal growth seahorse was only 61.09% of that in the slow growth seahorse, and the ratio of RNA/DNA in the normal growth seahorse was higher 23.75% than that of the slow growth seahorse. The growth, digestion and immunity of he normal growth seahorses were obviously better than those of the slow growing hippocampus when their body length were more 5.026 cm.
Molecular cloning of multiple vitellogenins in Scatophagus argus and their gene expressions after 17α-ethynylestradiol exposure in vivo and in vitro
Di WU, Meiqin WU, Maoliang SU, Yong ZHONG, Wu WANG, Junbin ZHANG
In Press  doi: 10.11964/jfc.20170410777
[Abstract](2465) [FullText HTML](1376) [PDF 3559KB](35)
Abstract:
With the aim to explore the molecular mechanism of vitellogenin (Vtg) in Scatophagus argus, we cloned the full-length cDNA sequence of three types of vtg by using reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) procedures. The length of the vtgAa cDNA is 5360 bp (GenBank No. KY676847), and it encodes a protein consist of 1696 amino acids. The length of the vtgAb cDNA is 5346 bp (KY654346), and it encodes a protein consist of 1699 amino acids. The length of the vtgC cDNA is 4244 bp (KY676848), and it encodes a protein consist of 1275 amino acids. Sequence analysis showed that three vitellogenin homologs of Scatophagus argus have highest homology with Morone americana (83%, 85% and 85%). VtgAa and VtgAb contain all the three major portions, but VtgC lacks phosvitin (PV). Quantitative real-time PCR (qPCR) assay were employed to determine the mRNA expression of vtgAb in the liver after 17 α-ethynylestradiol (EE2) injection in vivo and hepatocytes after exposure EE2 in vitro. Results of qPCR showed that the hepatic expression of vtgAb was higher than vtgAa and vtgC. 48 h after injection, mRNA expression of vtgAb was extremely increased and obviously decreased after 72 h. The expression of vtgAb mRNA was elevated after EE2 exposure to hepatic cells. Based on our results, expressions of vtgAb could be induced by EE2.
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2019, 43(8).  
[Abstract](253) [PDF 2611KB](7)
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2019, 43(8): 1-2.  
[Abstract](344) [FullText HTML](266) [PDF 268KB](5)
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Cloning and expression of sox9a/b gene in the large yellow croaker (Larimichthys crocea)
Meng ZHANG, Yangyang ZHU, Wanbo LI, Weiliang SHEN, Xiongfei WU, Kun YE, Zhiyong WANG
2019, 43(8): 1691-1705.   doi: 10.11964/jfc.20181111531
[Abstract](1881) [FullText HTML](1003) [PDF 1443KB](31)
Abstract:
To elucidate the role of sox9 in sex determination and differentiation of the large yellow croaker (Larimichthys crocea), the full length of sox9a and sox9b were cloned using reverse transcription-polymerase chain reaction (qRT-PCR) and rapid amplification of cDNA ends (RACE). The difference of the gene expression in various tissues and development stages was analyzed through quantitative real-time PCR. Expression profiles of sox9a/b after 17β-estradiol or 17α-methyl testosterone treatments were also examined. The full-length cDNA of sox9a gene is 2 442 bp (NCBI: MH996431), including a 476 bp 5′ UTR, a 466 bp 3′ UTR and a 1 500 bp ORF coding a polypeptide of 499 amino acids. The full-length cDNA of sox9b gene is 2 199 bp (NCBI: MH996432), including a 335 bp 5′ UTR, a 415 bp 3′ UTR and a 1 449 bp ORF coding a polypeptide of 482 amino acids.Quantitative Real-time PCR results showed that sox9a was primarily expressed in gonad, eye, brain, liver, and the expression level in testis was significantly higher than that in ovaries. sox9b was widely expressed in multiple tissues in large yellow croaker; the expression level was the highest in testes, but can be barely detected in ovaries. At early developmental stages of fry, sox9a/b was expressed at a lower level. Sox9a/b peaked at 84 dph (day post hatch) and 123 dph, then their expression declined and gradually rose again at 10 mph. In addition, 17β-estradiol can significantly down-regulate the expression of sox9a and sox9b in testes. 17α-methyl testosterone can significantly elevate the expression of sox9a and sox9b in gonads. The study demonstrated that sox9a/b may play important roles in sex determination and differentiation in the large yellow croaker. However, the functions of the two genes may be different.
Polymorphism of seven insert/deletion mutations and their connection with growth traits of juvenile grass carp (Ctenopharyngodon idella)
Meng ZHANG, Yubang SHEN, Xiaoyan XU, Rongquan WANG, Xiangjun LENG, Jiale LI
2019, 43(8): 1706-1713.   doi: 10.11964/jfc.20180911463
[Abstract](2000) [FullText HTML](987) [PDF 579KB](16)
Abstract:
A weight-related QTL was found in the 15 linkage group (LG) during mapping the growth traits of grass carp (Ctenopharyngodon idella). And we tried to screen insert/deletion mutations on three scaffolds in the 15 LG, according to the previous consensus linkage map and draft genome of C. idella. At the meantime, the STR genotyping method was uesed in genotyping of insert/deletion mutations. Moreover, the association analysis of selected mutations and growth traits of 323 individuals was conducted. Results found that 17 of the 44 selected insert/deletion mutations were SSRs, and 2 loci failed to design primers; therefore, 25 pairs of primer were successfully designed. PCR amplifications showed that only 22 of the 25 primer pairs were effective. Then STR genotyping method was used for genotyping of those 22 insert/deletion mutations, and 7 polymorphic mutations were found in four parents. Afterwards, PCR products were sequenced to confirm the STR genotyping results. Sequencing results showed that STR genotyping method could not only classify insertion/deletion mutants accurately, but also reduce the genotyping costs. Finally, the general linear model was used to analyze the relevance between those 7 insert/deletion mutations and growth traits of 323 juvenile C. idella. Correlation results found that 2 loci (ID-10H and ID-41F) were not related with growth traits, while the other 5 loci were significantly related with one or more growth traits of juvenile C. idella. According to the 5 loci, locus ID-6H was significantly correlated with fatness traits of juvenile C. idella, while locus ID-11F, ID-15F, ID-32F and ID-39F were significantly correlated with body weight or length or width or height. In summary, the inexpensive STR genotyping method could be used in the development of insert/deletion mutations, and the 5 growth related mutations could be used in QTL density-increasing and molecular marker assisted breeding of C. idella.
Transcriptome analysis of spotted steed (Hemibarbus maculatus Bleeker) to identify genes related to ovary development
Huifen LIU, Liangsheng LU, Jing WANG, Chuanjiang ZHOU, Qianhong GU, Xiao MA, Junchang FENG, Guoxing NIE, Xuejun LI
2019, 43(8): 1714-1722.   doi: 10.11964/jfc.20180811419
[Abstract](1700) [FullText HTML](963) [PDF 959KB](45)
Abstract:
In order to identify candidate genes involved in ovary development, Illumina Hiseq technology was used to define the transcriptome of spotted steed brain, ovary and liver. A total of 49 484 132, 47 540 538 and 50 622 304 clean reads were generated from brain, ovary and liver, and then assembled into 99 878 Unigenes with an average length of 1 430 bp. DEseq analysis revealed that 2 305 were found only in the expression of brain vs. ovary group, 839 were found only in the expression of brain vs. liver group, 1 474 were found only in the expression of ovary vs. liver group, and 860 genes were found to be co-expressed in the three comparison groups. Gene ontology analysis indicated that many of these genes encoded proteins involved in primary metabolic process, single-organism process, organic substance metabolic process. Based on KEGG pathway analysis, putative genes are novel candidate regulators of oocyte development and meiosis, such as GnRH signaling pathway, Steroid hormone biosynthesis, TGF-beta signaling pathway and Oocyte meiosis. The spotted steed transcriptome data reported here will provide valuable new data to increase genomic resources of this species. The data will also provide a valuable basis for further reproductive molecular biology studies of this commercial species.
Effects of pH and carbonate alkalinity on survival rate, Na+/K+-ATPase activity and phagocytic ability of the razor clam (Sinonovacula constricta)
Bo YE, Zhiyang CHENG, Maoxiao PENG, Donghong NIU, Xiaojun LIU, Tianyi LAN
2019, 43(8): 1723-1732.   doi: 10.11964/jfc.20180611329
[Abstract](1076) [FullText HTML](536) [PDF 991KB](18)
Abstract:
In this study, a static toxicology experiment was conducted to analyze the survival rate, Na +/K+-ATPase (NKA) activity and phagocytic ability of the hemolymph of Sinonovacula constricta of two different sizes (small-size SSc and large-size LSc) under the acute stress of high pH and carbonate alkalinity (CA). The results showed that when the CA concentration was 2.5 mmol/L and the pH was 7.5−9.5, the survival rates of the two sizes were close to 100%.When the pH value was greater than 9.5, the survival rates of the two sizes were significantly decreased.When the concentration of CA was 0−44.58 mmol/L and the pH value was 9.0−10.0, the survival rate of clams decreased with the increase of CA concentration. Under the condition of pH 9.5, the NKA activity of LSc gill tissue increased with the increase of CA concentration, and the phagocytic capacity of LSc haemolymph decreased with the increase of CA concentration. It can be seen that S. constricta showed strong tolerance to high pH or CA, but high pH and CA had a great effect on the survival rate of S. constricta. The research results provide a theoretical reference for further exploration of breeding of S. constricta in saline-alkali soil.
Microstructure and ultrastructure of zebrafish heart
Xindong WANG, Xuejing SUN, Qiaoya ZHAO, Yufei HUANG, Qiusheng CHEN, Jinxing LIN
2019, 43(8): 1733-1748.   doi: 10.11964/jfc.20181011478
[Abstract](1627) [FullText HTML](789) [PDF 256268KB](21)
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In this paper, the microstructure and ultrastructure of zebrafish heart were observed by light microscopy and transmission electron microscopy. The results showed that the heart of zebrafish was composed of four parts: ventricle, atrium, bulbous arterious and venous sinus. The ventricle is brown-red and the stratification was obvious, it was divided into a compact layer of the epicardial region and a sponge layer of the endocardial region. The atrium is bright red and consists only of a loose sponge layer. An arterial trunk (abdominal aorta) was issued in front of the ventricle and the starting part of the arterial trunk expands into ellipsoidal shape, called the bulbous arterious. The bulbous arterious was pear-shaped, which can be divided into three layers from the inside to the outside, and they were the inner layer, the middle layer and the outer layer respectively. The venous sinus was difficult to isolate separately, therefore, the sinus was not isolated and observed separately. In this paper, the presence of telocyte interstitial cells was observed in the ventricles, atrium and arterial spheres. Their morphology was slender and long and could be divided into podomeres and podoms. The presence of multivesicular bodies was observed in the cardiomyocytes of the ventricles, which were often distributed on the outer edge of the cardiomyocytes, close to the sarcolemma or adjacent to the mitochondria of the outer edge of the cardiomyocytes.
Spatial distribution characteristics and seasonal variation of Oratosquilla oratoria in the southern coastal waters of Shandong Province
Mingkun LI, Binduo XU, Ying XUE, Chongliang ZHANG, Yiping REN, Jing WANG
2019, 43(8): 1749-1758.   doi: 10.11964/jfc.20181011488
[Abstract](1579) [FullText HTML](750) [PDF 2048KB](19)
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The present study analyzed the spatial distribution of Oratosquilla oratoria in the southern coastal waters of Shandong Peninsula based on bottom-trawl surveys in October 2016, January 2017, May 2017 and August 2017. We used center of gravity and Moran’s I index to estimate the distribution center of this species, compared the seasonal differences of spatial autocorrelation, and explored the potential influential factors of the spatial patterns. This study found substantial seasonal variations in the relative biomass of O. oratoria, which showed the highest relative biomass of 3.02 kg/h in summer, followed by 0.75 kg/h in spring, 0.65 kg/h in autumn and 0.22 kg/h in winter. The center of gravity showed remarkable seasonal changes, with the corresponding water depth ranging from 20 m to 30 m in spring and summer and from 30 m to 50 m in autumn and winter. The distributional pattern of O. oratoria was relatively consistent, exhibiting significantly positive spatial autocorrelation in four seasons. Moran’ I index was the highest in autumn (0.34), followed by spring (0.30) and summer (0.28), and was the lowest in winter (0.16). According to Moran’ I scatterplots, we identified survey sites with strong influence on biomass concentration. The seasonal changes in spatial distribution of O. oratoria might attribute to its spawning activities, and the biomass concentration implied that muddy silt and sand-silt-clay were the preference of sediment types of O. oratoria. We discussed the implications of our results for the management of O. oratoria and put forward the priorities for future fisheries research on spatial analyses.
Relationship between spatio-temporal distribution of Conger myriaster and the environment factors in the southeast waters of Shandong Peninsula
Xiuxia MU, Mingkun LI, Jie YIN, Chongliang ZHANG, Yiping REN
2019, 43(8): 1759-1767.   doi: 10.11964/jfc.20181011514
[Abstract](1469) [FullText HTML](858) [PDF 930KB](34)
Abstract:
Environmental changes have caused shifts in the population abundance, size structure, and habitat distribution of many marine fish species, and the impacts tend to aggravate with the future global climate changes. A better understanding of the relationship between the fish distribution and environment is helpful in coping with the further changes of climate and fisheries. Based on survey data of fishery resources and the habits collected from 99 stations in January, May, and August, 2017 and October, 2016 in Shandong offshore, we analyzed spatiotemporal distribution of Conger myriaster, and examined its relationship with environmental variables, including water depth, bottom salinity, bottom water temperature, bottom sediment types and prey density, using generalized additive model (GAM). The result showed significant seasonal variations in the distribution of C. myriaster. The stock density was 66.38 kg/h in spring, 87.31 kg/h in summer, 79.01 kg/h in autumn and 10.44 kg/h in winter. GAM identified depth and bottom water temperature as the major influencing environmental factors. In spring, both depth and sea bottom temperature had positive correlations with resource density of C. myriaster which was primarily distributed in the central part of Haizhou Bay, especially at latitudes 35°N. In summer, stock density of C. myriaster was influenced by water depth, and mainly distributed in the south coastal waters of Shandong Peninsula. Water depth, water temperature and prey density had positive relationships with resource density of C. myriaster in autumn. In winter, resource density of C. myriaster had a positive relationship with water depth, and north of Haizhou Bay and longitude 123.5°E-124.0°E were its main distribution area. The distribution of C. myriaster might be attributed to its migratory habits and the variation of the environment conditions caused by seasonal changes, such as water temperature, Qingdao cold water mass and Yellow Sea warm current.
Effects of water salinity on the growth, ovarian development, osmoregulation, metabolism and antioxidant capacity of adult female swimming crab(Portunus trituberculatus)
Xiaowen LONG, Renfu WU, Wenjie HOU, Guiping PAN, Yongxu CHENG, Xugan WU
2019, 43(8): 1768-1780.   doi: 10.11964/jfc.20180611338
[Abstract](1895) [FullText HTML](930) [PDF 911KB](30)
Abstract:
In order to investigate the effects of long-term salinity adaptation on growth, ovarian development, osmoregulation, metabolism and antioxidant capacity of adult female swimming crab (Portunus trituberculatus), adult female P. trituberculatus post puberty molt was subjected to four water salinities (10, 15, 20 and 25) for 60 days. The results showed as follows: The survival rate, weight gain rate, specific growth rate and gonadosomatic index of female crabs increased significantly with increasing water salinity. The serum osmolality and the contents of Na+, Cl-, Ca2+, Mg2+ and major free amino acids, and total free amino acids in the serum, as well as the posterior gills Na+/K+-ATPase activity showed an overall increasing trend with increasing water salinity. The contents of serum glucose and hepatopancreas lactic acid decreased significantly with increasing water salinity, while the levels of serum urea nitrogen, uric acid, and hepatopancreas uric acid showed an increasing trend. The higher contents of triglyceride, total cholesterol and urea nitrogen in the hepatopancreas were detected in 20 and 25 salinity treatments. The activity of total superoxide dismutase in the serum and hepatopancreas of females from 10 salinity treatment was significantly lower than that of other salinity treatments, while the highest levels of total antioxidant capacity, glutathione peroxidase, γ-glutamyl transpeptidase and hemocyanin in the serum, as well as and hepatopancreas glutathione peroxidase and malondialdehyde were detected at 10 salinity treatment. In conclusion, elevating water salinity could promote the growth and ovarian development of adult female P. trituberculatus, and the females had lower levels of metabolism and oxidative stress under the conditions of 20 and 25 salinities.
Effects of ecological operation of Three Gorges Reservoir on larval resources of the four major Chinese carps in Jianli section of the Yangtze River
Xue ZHOU, Ke WANG, Daqing CHEN, Shaoping LIU, Xinbin DUAN, Dengqiang WANG, Lei GAO
2019, 43(8): 1781-1789.   doi: 10.11964/jfc.20180711365
[Abstract](1914) [FullText HTML](899) [PDF 905KB](16)
Abstract:
In order to explore the effect of ecological operation of Three Gorges Reservoir on breeding of the four major Chinese carps in Jianli section of the Yangtze River, and evaluate the quantitative range of ecological hydrology indexes that stimulate spawning behavior of four major Chinese carps, in this study, we investigated the early life resources of the Four Major Chinese Carps in Jianli section of the middle reaches of the Yangtze River, from May to July, 2013—2017. Correlation analysis was made between the Four Major Chinese carps’ spawning and larvae collected and the ecological hydrology index. The results show that there is a significantly positive correlation between the daily flow increasing rate and the quantity of fish eggs. When the duration is 4 d and more, and the daily flow increasing rate is from 1 600 to 2 833 [m3/(s·d)], ecological operation is more effective to stimulate the reproduction of the Four Major Chinese Carps in late June. Preliminary results indicated, water rising of ecological operation of Three Gorges Reservoir has improved the hydrological conditions for the breeding of four major Chinese carps in Jianli section. The implement of ecological operation not only reduced the negative impact on fish breeding in the midstream of the Yangtze River, but also maintained fish population resources after the operation of the Three Gorges Reservoir.
Optimization of the Manila clam(Ruditapes philippinarum) breeding technique in diked tidal flat and the impact on physicochemical indices, phytoplankton community and juvenile growth performance
Jianfei QI, Yayou ZHENG, Qisheng WU, Yue NING, Xiang GUO, Zhinan ZENG, Yuanyuan JIA
2019, 43(8): 1790-1797.   doi: 10.11964/jfc.20180611340
[Abstract](2197) [FullText HTML](1009) [PDF 868KB](16)
Abstract:
The Manila clam (Ruditapes philippinarum), with annual yield of 4 million tons in 2015, is a kind of important economic shellfish in China. The breeding technique in diked tidal flat which is the most productive technology, is not particularly reliable. In order to optimize it, a pond (A) was set up to induce phytoplanktonic blooms, which was regularly distributed to the nursery pond (B), and nursery pond (C) without algae superinduced as the control. The water, sediment quality and phytoplankton of A, B, C were compared with those of adjacent natural sea area (D). The growth of juveniles in B and C were also compared. The results showed that, there was no significant difference between A, B and C in water and sediment quality, but the water quality parameters(S, pH, DO, NH3-N, NO3-N, PO4-P) and the sediment quality (organic carbon, sulfide) of the three ponds were significantly different from D; the phytoplankton density followed the order of A > B > C > D, but only A had significant difference with D; the shell length and density of juveniles in B were significantly higher than those in C. This indicated that there was a great difference in the environment between the diked tidal flat ponds and the natural sea area, and phytoplankton supplement can increase the growth and survival of the juveniles, thus ensuring the success rate of the breeding of R. philippinarum in diked tidal flat ponds.
Effects of feeding methods of carbon sources on the water treatment of suspended growth reactors in a recirculating aquaculture system
Wenchang LIU, Hongxin TAN, Guozhi LUO, Wei CHEN, Nannan ZHANG, Yongxia YU, Miaolan YAO, Pronapinyakun PIMPRON
2019, 43(8): 1798-1807.   doi: 10.11964/jfc.20180411257
[Abstract](1596) [FullText HTML](808) [PDF 1065KB](16)
Abstract:
A suspended growth reactor under continuous carbon resource feeding method (SGR-Con) and another under several steps carbon resource feeding method (SGR-Sev) were operated in a pilot-scale recirculating aquaculture system to compare their water treatment efficiency. It indicated that the concentrations of dissolved organic carbon in the reaction zone of SGR-Con was at a high and stable level, while that in SGR-Sev firstly increased to the same level of SGR-Con during the 0 h in cycle to the instantaneously carbon feeding time and it subsequently decreased to a lower and stable level after 4 h in cycle. Dissolved oxygen in the reaction zone of SGR-Sev, as well as the settling zone was significantly higher than that in SGR-Con. The pH in the reaction zone between different reactors had no significant difference, and it was same in settling zone. Several steps carbon resource feeding method significantly increased the nitrogen removal of reactor. Overall the experimental period, the removal rate of nitrate and total nitrogen in SGR-Sev could be 63.91%±14.31% and 64.07%±12.11%, respectively. Besides, alkalinity in the effluent of SGR-Sev was (278.18±80.33) mg/L. SGR-Sev was favorable to achieve good settling performance of bio-flocs. However, the concentrations of total ammonia nitrogen and nitrite in the effluent of SGR-Sev were higher than those of SGR-Con. In summary, it is better to adopt the several steps carbon resource feeding method for suspended growth reactors.
Correlation analysis of fish growth performance and serum hormone and digestive enzyme activities of juvenile pearl gentian grouper (Epinephelus lanceolatus♂×E. fuscoguttatus♀) fed with different protein levels diets
Xinwei GUO, Beiping TAN, Shuyan CHI, Xiaohui DONG, Qihui YANG, Hongyu LIU, Shuang ZHANG
2019, 43(8): 1808-1820.   doi: 10.11964/jfc.20180711385
[Abstract](1585) [FullText HTML](816) [PDF 834KB](19)
Abstract:
An 8-week feeding trial was conducted to assess the correlation of the dietary protein with growth of juvenile pearl gentian grouper (Epinephelus lanceolatus♂×E. fuscoguttatus♀), serum hormone and digestive enzyme activities, to explore the effects of dietary protein levels on healthy growth. Grouper [average body weight (6.50±0.00) g] were randomly divided into 6 groups with 4 replicates in each group. The fish were fed isoenergetic and isolipidic experimental diets with protein levels 35%, 40%, 45%, 50%, 55% and 60%, respectively. The results showed that weight gain rate and specific growth rate of the fish fed with 50% protein diet were significantly higher than those of fish fed other protein level diets. The concentrations of total protein (TP) in 50% group and 60% group were significantly higher than 35% group. The concentrations of growth hormone (GH) and insulin (INS) in 50% group were significantly lower than those in other groups. The highest insulin-like growth factors-Ⅰ (IGF-Ⅰ) concentration was found in 45% group and significantly higher than those in other groups. Pepsin and intestinal trypsin activities in 50% group were significantly higher than those in other groups. With increasing dietary protein levels, intestinal amylase activity was decreased, the lowest value was found in 55% group and 60% group and significantly lower than those in other groups. There was extremely significantly negative correlation between WGR and GH. According to these results, based on broken-line regression analysis of WGR, a diet containing 51.57% protein is recommended for efficient growth of juvenile pearl gentian grouper.
Effects of LED spectrum on feeding, growth and energy distribution of juvenile Dicentrarchus labrax
Jilong REN, Pingping WEI, Fan FEI, Mingyun DAI, He MA, Dongkui GAO, Changbin SONG, Tao CHEN, Ying LIU
2019, 43(8): 1821-1829.   doi: 10.11964/jfc.20181111534
[Abstract](1541) [FullText HTML](784) [PDF 657KB](14)
Abstract:
Dicentrarchus labrax is an important economic fish in aquaculture in China. In the process of industrialized recirculating aquaculture, different spectral environments have important implications for the effects of feeding and growth. In this study, five different LED spectral processing groups of white light (λ400-780 nm), red light (λ630 nm), yellow light (λ595 nm), green light (λ530 nm) and blue light (λ455 nm) were set in the seawater circulating aquaculture experimental system. The effects of five different LED spectra on feeding, growth and energy distribution of juveniles [(29.91±0.39) g, (13.78±0.35 cm)) were studied. The results showed that the effects of different LED spectra on the feeding, growth and energy distribution of juveniles were significantly different. The red light group had the best growth of the juveniles (41.09±5.70) g, and the blue group had the poorest growth of the juveniles (36.02±4.18) g; the DGC (daily growth coefficient) of the blue group was significantly lower than the other groups, and the difference between the other groups was not significant; there were significant differences in the feeding rate of the three groups of LED spectrum treatment groups, and the red light group had the highest feeding rate. The results of insulin-like growth factor IGF-1 and IGF-2 showed that the expression of IGF-1 mRNA was highest in the white light group; the mRNA expression level of IGF-2 was highest in the yellow light group. In terms of energy distribution, the red light group has lower fecal energy and metabolizable energy, and has the highest feeding energy and growth energy; the blue light group has the highest fecal energy, lower feeding energy and metabolic energy, and the lowest growth energy. The ratio of RNA/DNA in the muscle and liver of juvenile fish showed that the RNA/DNA ratio of the liver in the blue light group was significantly higher than that in the other groups; the RNA/DNA ratio in the muscles of the blue light group and the white light group displayed significant difference and no significant differences existed among the other groups. The results showed that the red light Eurasian larvae had better feeding and growth performance, and the blue-spectrum larvae had poor feeding and growth performance, and the red-spectrum larvae had higher feeding energy and growth energy. Therefore, the red spectrum has a better promoting effect on the growth of juveniles , and the blue spectrum has an adverse effect on the feeding growth of juveniles. This study provides a reference for the ground-based industrialized recirculating aquaculture of the D. labrax, creating a suitable spectral environment for growth.
Construction of glycoprotein gene nucleic acid vaccine against infectious hematopoietic necrosis, and its effect on serum biochemical indices
Qiyao HE, Wenyan WEI, Kaiyu WANG, Jiaxing LIU
2019, 43(8): 1830-1838.   doi: 10.11964/jfc.20180711378
[Abstract](2695) [FullText HTML](1441) [PDF 984KB](14)
Abstract:
The aim of this study was to study the effect of infectious hematopoietic necrosis virus (IHNV) nucleic acid vaccine on the immune protection of Oncorhynchus mykiss and serum biochemical indices of Oncorhynchus mykiss. Cloning the glycoprotein gene (G) into pMD19-T vector, we transformed the linked product in DH5α, obtaining recombinant plasmid pMD19-T-G, and recovering the G gene fragment. The identified correct G gene fragment was cloned on eukaryotic expression vector pVAX1 using BamH I and Xho I cleavage sites to construct nucleic acid vaccine pVAX1-G. The recombinant plasmid pVAX1-G was injected into O. mykiss at a dose of 8 μg/ind. as pVAX1-G group, while 8 μg/ind. empty group, PBS control group and blank group were set up. Twenty-one days after immunization, an anti-virus experiment was carried out. After anti-virus, serum was collected and blood indexes were tested. The results showed that there were significant changes in 16 indexes in O. mykiss serum after the attack: glutamic-pyruvic transaminase (ALT), glutamate transaminase (AST), alkaline phosphatase (ALP), total bilirubin (TBIL), total bile acid (TBA), glucose (GLU), the urea (Urea), creatinine (CREA), total protein (TP), albumin (ALB) and globulin (GLO) were compared with normal O. mykiss, and the changes of 11 indexes in no-load group were more significant than those in pVAX1-G group. The cumulative death rate of pVAX1-G group was 19%(19/100)14 days after the attack, while that of no-load group and PBS control group was 62%(62/100) and 85%(85/100), respectively. The protective rate of pVAX1-G nucleic acid vaccine for O. mykiss was 78%. The results showed that pVAX1-G as a nucleic acid vaccine was helpful to reduce IHNV’s injury to O. mykiss and had better immune protection effect against IHNV.
Effects of different thawing ways and multiple freeze–thaw cycles on myofibrillar protein intermolecular force of Sepia esculenta
Hongchao ZHANG, Zhangzhi XUE, Yuan DING, Xiaorong XU, Yang JIN, Hesheng LI, Hongfei WANG, Feng XU
2019, 43(8): 1839-1849.   doi: 10.11964/jfc.20180711383
[Abstract](1995) [FullText HTML](939) [PDF 1368KB](13)
Abstract:
This study explored the effects of multiple freeze-thaw cycles on myofibrillar protein intermolecular force of Sepia esculenta and its protein properties. Fresh S. esculenta meat were defrosted by three different ways which are 0 °C, running water and normal temperature for 9 freeze-thaw cycles. The results showed that the effects of defrosting ways were significant on intermolecular forces, and thaw at 0 °C is better than running water and normal temperature. With the increase of freeze-thaw times, the content of ionic bond and hydrogen bond showed a significant decline, the ionic bond decreased by 7.71%, 10.64% and 13.61%, respectively, and the hydrogen bond decreased from 31.91%, 31.97% and 31.87% to 26.76%, 25.53% and 23.94%. On the contrary the hydrophobic interaction force, disulfide bond and non-disulfide covalent bond tended to increase, the hydrophobic forces increased by 8.86%, 12.35%, and 14.72%, respectively, and the disulfide bonds increased by 1.43%, 1.96%, and 2.85%, respectively, the non-disulfide covalent bonds increased from 1.16%, 1.28%, and 1.55% to 3.75%, 4.05% and 5.50%. The surface hydrophobicity of myofibrillar protein increased from 30.47 μg, 31.31 μg and 32.26 μg to 46.10 μg, 53.51 μg and 58.91 μg, respectively, consistent with hydrophobic force results. Both sulfhydryl and reactive thiol content were decreased, the sulfhydryl groups were reduced by 13.07 nmol/mg, 38.99 nmol/mg and 40.32 nmol/mg, respectively, and the active sulfhydryl groups were decreased by 6.55 nmol/mg, 24.26 nmol/mg and 43.16 nmol/mg, consistent with disulfide bond generation trends. The changes of the secondary structure of myofibrillar protein were analyzed by Infrared spectroscopy (FTIR), indicated that during the freeze-thaw cycles the spatial conformation of myofibrin made a change. Three thawing ways were treatments after 9 freeze-thaw cycles, the spectral band shifted to different wavelength regularly, and the amide A band and the amide Ⅲ band moved slightly toward the high wave number direction, and the amide Ⅰ band and the amide Ⅱ band moved to the low wave number direction. The secondary structure of the protein changed, as the sum of the contents of both α-helix and β-sheet reduced, and the sum of the contents of β-turn and random curl increased. Repeated freezing and thawing is actually a process of slow oxidation of proteins.

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