Abstract:In order to understand the formation of black pattern in Oujiang color common carp,and to learn the important function of pigment related gene. and further study the molecular mechanism of black patterns formation in Oujiang color common carp or other fishes, so in this study, the melanin development was first observed in RB and WR. Meanwhile, the in situ probe of mitfa was prepared for analysing the exprssion and localization of mitfa gene in the important period of melanin development, according to the observation of the development of melanin in RB and WR in 9 development periods. In RB, the melanin appeared in the eyes at 36 hpf firstly, the melanin was first observed on the body at 3 dph, then melanin appeared locally at tail, abdomen and dorsal. In WR, the melanin only happened in the eyes, no melanin was observed in other position. Whole-mount in situ hybridizaton mitfa gene showed that the hybridization signal appeared on the head and abdomen where melanin appeared. When the melanin significantly increased at 10 dph, hybridization signal increased and more obvious. But even these is no melanin in the body of WR, the mitfa gene hybridization signal also can be observed. This study suggests that mitfa gene plays an important role of melanin in Oujiang color common carp,but it is not responsible for the difference of black pattern between several Oujiang color common carp.

Abstract:Sinonovacula constricta was used as the research species. Acute low salinity stress method was used, and the survival rate, Na⁺/K⁺-ATPase (NKA) activity and phagocytosis of hemocytes of S. constricta were measured. The results showed when the salinity was set from 8 to 2, the survival rate of three different sizes S. constricta were almost 100%, the NKA activity kept relatively stable, and the phagocytic capacity of hemocytes only had a small range of decline. When salinity was set from 2 to 0, the survival rate of three different sizes S. constricta decreased with the decrease of salinity, and the survival rate of adult was higher than that of the sub-adult and juvenile all the time. The NKA activity was correspondingly increased to maintain the osmolality balance inside and outside of the body. It is believed that the physiological function of S. constricta was affected by salinity acute decrease, so the phagocytic capacity of hemocytes was reduced. The low salinity LC₅₀ of juveniles, sub-adults and adult were 1.45, 1.25 and 0.75, respectively. In summary, S. constricta has a strong tolerance to acute low salinity and could be a potential inland aquaculture species.

Abstract:The cDNA of cyclin B gene was cloned from Hyriopsis cumingii by modern molecular biology techniques, and the sequence length is 1 024 bp, including 768 bp of ORF, 197 bp of 3'-UTR, encoding 255 Aa. Further analysis showed that cyclin B has a high similarity with oysters and scallops. Its amino acid sequence has a typical cyclin-box and two cyclin-dependent protein kinases, the site of action of CDK.RT-Q PCR showed that the expression of cyclin B was the highest in the gonads, and the expression level of cyclin B in females was significantly higher than that in males (P<0.05). The expression of cyclin B in other tissues was significantly lower than that in gonad (P<0.05), and there was no significant difference between male and female (P>0.05).After RNA interference (RNAi), the expression of gonad and gill was significantly decreased except for the mantle (P<0.05), indicating that RNAi has different silencing effects on different tissues of Hyriopsis cumingii. The phase changes of cells after RNAi were determined by flow cytometry. It was found that the proportion of G2/M phase in gonad and gill cells decreased, indicating that cell division can be regulated by cyclin B in Hyriopsis cumingii.The cyclin B gene and its preliminary functions were studied, which laid a molecular basis for further regulation of the cell growth in vitro.

Abstract:In order to investigate the effects of reducing feeding amount of bait and dredging on water environment of aquaculture bay, four treatment groups were set up on the basis of 20 g/m³ stocking density of silver carp and bighead carp,which were B1 (no dredging, half feeding of bait), B2 (dredging, no feeding), B3 (dredging, half feeding of bait), B4 (no dredging, normal feeding of bait). The experimental period was 9 months. Results showed as follows:The total nitrogen concentration, total phosphorus concentration, permanganate index and algae biomass from low to high were B2, B4, B1, B3; B2, B1, B4, B3; B2, B1, B4, B3; B2, B1, B3, B4 (P<0.05), respectively. There was no significant difference in zooplankton biomass (P>0.05). B2 achieved the best results in both the control of nutrient salt and algae.As the aquaculture bay, its main function is to get higher fish production. Under the condition of meeting the requirements of aquaculture water quality, the rational use of the bait should be taken to obtain higher fish production. Therefore, for the treatment of aquaculture water, the reasonable remediation methods should be adopted according to the specific water quality conditions in order to achieve a win-win situation of water quality improvement and aquaculture production.

Abstract:To study the effects of different fertilization modes on the water bacteria in rice-crayfish co-culture paddy field, Illumina high-throughput sequencing technology was used to detect the bacteria in the water body applying three fertilization modes:chemical fertilizer (CF), organic fertilizer (OF) and organic fertilizer added decomposed chicken manure (OM). The results showed that Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria and Firmicutes were the main phyla in all treatments. The main dominant genera were Sporichthyaceae hgcl_clade, Limnohabitans, Polynucleobacter, Alpinimonas, Comamonadacea, Hydrogenophaga. In the three models, the bacterial abundance of the OF group was significantly higher than that of the CF group and OM group, and the diversity of bacterial species of OF group was significantly higher than that of the OM group, and there was no significant difference between OF and CF groups. It indicated that in the mode of organic fertilizer application, water microorganisms had better diversity and its ecosystem was more stable. Although the OM treatment reduced the species diversity of bacteria in water, it also can greatly reduced the abundance of Cyanobacteria. Although the species diversity of bacteria in water was reduced under OM treatment, it also greatly reduced the abundance of Cyanobacteria compared to other treatments. The results of cluster analysis showed that the similarity of bacterial community in water was higher between the OF group and OM group. According to the RDA analysis, the dissolved oxygen, total nitrogen, pH and total phosphorus were the most important environmental factors affecting water bacteria. The aim is to understand the effects of different fertilization treatments on the ecological environment of paddy fields and provide a theoretical basis for the optimization of paddy field comprehensive fertility model.

Abstract:Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic organic pollutants composed of two or more benzene rings and are widely present in various environmental media. In order to understand the health risk of PAHs in Macrobrachium rosenbergii (M.rosenbergii) in the culture ponds in Jianguo Road,Caojing Town,Jinshan District,Shanghai,16 PAHs collected from M.rosenbergii in Jinshan District from July to September 2018 were determined.Concentrations were analyzed for cumulative characteristics over time and their potential food risks were calculated.The results showed that except for ANY,ANA,DBA,IPY and BPF,the other 11 PAHs were detected in different degrees.The concentration of ∑PAHs in M.rosenbergii in different periods ranged 47.6-106 ng/g dw.The dominant components of PAHs were 3- or 4-ring structure,of which 4-ring compounds accounted for the highest proportion,and the dominant monomers were ANT,BaA and CHR.Traceability analysis showed that the PAHs in the pond are mainly derived from the combustion sources.Using the US Environmental Protection Agency's (USEPA) recommended health risk model to evaluate the health risks caused by the consumption of Macrobrachium rosenbergii,the ILCR value of PAHs in M. rosenbergii culture farms in Jinshan District was at an acceptable level and would not have impact on the human health.

Abstract:In order to investigate the influences of water temperature and vehicle swaying on the survival rate of juvenile fish for stock enhancement during the process of transportation, the changes of environmental water ammonia nitrogen mass concentration, the changes of muscular lactic acid concentration and glycogen mass fraction of juvenile Acanthopagrus schlegelii, at different water temperature and different levels of swaying simulation. When the environmental water temperature was elevated, increased ammonia nitrogen concentration in water was observed, while the muscular lactic acid concentration of juvenile fish increased at early stage and then decreased later, whereas the muscular glycogen mass fraction of juvenile fish varied in the opposite way, decreased at early stage and then increased later. The survival rate of juvenile fish dropped significantly with the increase of environmental water temperature, and 21 to 25℃ were regarded as optimal water temperature. In the swaying simulation experiments, when the swaying frequency of environmental water was enhanced, increased ammonia nitrogen mass concentration in water was observed, while the juvenile fish was observed with increased muscular lactic acid concentration and decreased muscular glycogen mass fraction. The survival rate of juvenile fish dropped significantly with the enhancement of environmental water swaying. It is recommended that the black sea bream juveniles with a size of about 5 cm should be trained for the black sea bream juveniles before transport, and the stress factors such as water temperature and shaking should be trained. The water temperature during transportation should not exceed the water temperature under the indoor cultivation conditions. 21-25℃ are appropriate, and can be lower than the water temperature under its indoor cultivation conditions, but the temperature difference should not exceed 4℃, while the shaking frequency during transportation should not exceed 105 r/min.

Abstract:To investigate the effects of different C/N ratios on the growth and cell biochemical components of Chlorococcum sp. Chlorococcum sp. was cultured with C/N ratios of 0:1, 3:1, 6:1, 9:1, 12:1 and 15:1 for 7 days, and the initial inoculation density was 300×10⁴ cells/mL. The results showed that mixotrophic cultivation could significantly increase cell density, specific growth rate and biomass (P<0.05). While the ratio of C/N was 9:1, the biomass reached the maximum value of 0.36 g/L. Under mixotrophic cultivation, the protein and total lipid mass fraction of Chlorococcum sp. decreased with the increasing of C/N. When C/N was 12:1 and 15:1, the protein and total lipid mass fraction reached the minimum values of 33.76% and 6.67%, respectively. Carbohydrate mass fraction increased firstly and then decreased with the increasing of C/N. Furthermore, the maximum value (30.57%) was obtained by 9:1 group which was significantly higher than other groups (P<0.05). The mass fraction of saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) increased with the increasing of C/N ratios with the maximum values in 15:1 group. By contrast, increasing of C/N ratios had an adverse effect on polyunsaturated fatty acid (PUFA) content of Chlorococcum sp. with the minimum value (64.67%) in 15:1 group. It is concluded that the moderate up-regulation of C/N ratios could increase the biomass and promote the synthesis of SFA and MUFA of Chlorococcum sp., but not for PUFA.

Abstract:Nutritional composition, mineral elements, amino acids and fatty acids in muscle were investigated in Cyprinus carpio var. color from Qingtian and Jinhua. Results showed that contents of crude fat(fresh weight) in Qingtian Cyprinus carpio var color(QC) were significantly higher than that in Jinhua Cyprinus carpio var. color (JC) (P<0.01); 17 amino acids were obtained in both populations. The percentage of all amino acids in JC were higher than those in QC but Glycine and Cystine(P<0.05); Based on the criteria of amino acid score (AAS), the top two limiting amino acids in QC were Valine and Methionine+Cysteine, and the top two limiting amino acids in JC were Methionine+Cysteine and Valine; 16 fatty acids were detected in all muscle samples. C16:1, C18:1n9c, C18:3n3 and monounsaturated fatty acid in QC were higher than those in JC (P<0.05); C18:0 and C20:4n6 in JC were higher than those in QC(P<0.05). The contents of Zn and Cu in QC were significantly higher than those in JC(P<0.05), and the contents of Ca, P and Mg in JC were significantly higher than those in QC(P<0.05).

Abstract:In order to study the effect of dietary replacement of fish oil by vegetable oil on the crude lipid content and fatty acid composition of Chinese mitten crab, vegetable oil[m (soybean oil):m (rapeseed oil)=3:1] was used to replace different levels (0%, 50% and 100%) of fish oil to make three kinds of feeds with equal nitrogen and fat (F1, F2 and F3). The results showed that there was no significant difference (P<0.05) in the crude fat content between the meat, gonads and hepatopancreas of three groups of crabs. The fatty acid composition of each feed was different. The content of polyunsaturated fatty acid (PUFA) in meat was about 50%, and there was no significant difference (P>0.05) among dietary groups. The gonad fatty acid composition was affected by the fatty acid composition of feed. The content of n-6 PUFA increased with the increase of the replacement level. The hepatopancreas fatty acid composition was the most affected by the substitution of vegetable oil in the feed for fish oil, and the total content of monounsaturated fatty acid (MUFA) and PUFA increased with the replacement level. Compared with F1 and F3 groups, the contents of EPA+DHA in the edible parts of F2 group was relatively higher. It could be seen that 50% vegetable oil replacing fish oil was beneficial to the fatty acid composition of edible parts of female Chinese mitten crab. This study provided a reference for the substitution ratio of fish oil in the fattening feed and further improvement of the quality.

Abstract:β-defensin are a series of cationic small molecule antibacterial peptides rich in cysteine. They play an important role in protecting mammals and aquatic organisms such as fish and shellfish from pathogenic microorganisms, and are important protein immune factors in the body's specific immune system. The primary structure of Mandarin fish (Siniperca chuatsi) β-defensin (ScBD) consists of a signal peptide region on the N-terminal and a mature peptide region on the C-terminal. The mature peptide is responsible for the biological activity of ScBD. The objective of the present study is to construct a recombinant Pichia pastoris strain producing Mandarin fish β-defensin was constructed to solve the source problem of small molecule antimicrobial peptide, a natural endogenous immune factor. The gene ScBD encoding Mandarin fish β-defensin mature peptide was isolated from the spleen of Mandarin fish by RT-PCR. After linking it with the expression vector pPICZαA, pPICZαA-ScBD was transferred to P. pastoris X-33. Positive transformants were screened by YPD plate containing high concentration of zeocin, and the expression was induced by 1% methanol for 96 h at 28℃, 250 r/min and pH 6.0. The products of recombinant P. pastoris were purified by nickel ion affinity chromatography,and the purified product was identified by MALDI-TOF/TOF mass spectrometry. The antibacterial activity of the recombinant strain products was detected by plate coating method and turbidimetric method. The results showed that the primary structure identification based on mass spectrometry demonstrated that the purified product was the expected recombinant ScBD with a molecular weight of 6.35 ku;The bacteriostatic test results showed that the inhibition rates of the recombinant strains products on Staphylococcus aureus, Bacillus subtilis and Vibrio parahemolyticus were 94.34%, 86.97% and 85.92%, respectively. The recombinant P. pastoris strain constructed could effectively synthesize the recombinant ScBD with biological activity, which provides a technical approach for further development of natural small molecule antimicrobial peptides from fish.

Abstract:This study evaluated the bactericidal effects were evaluated against Vibrio parahaemolyticus by acidic electrolyzed water (AEW) combined with ultrasound which is a method different from the traditional sterilization methods. The effects were compared by viable plate count analysis. The physiological response was studied by scanning electronic microscopy (SEM) and cell membrane permeability revealed by protein leakage. Flow cytometry analysis revealed changes in the physiological states of V.parahaemolyticus. The effects of the combination of SAEW and ultrasound on the reductions of V.parahaemolyticus were evaluated in comparison with acidic electrolyzed water or ultrasound. The results revealed that AEW combined with ultrasonic showed bacterial reduction in V.parahaemolyticus by 2.09 log CFU/mL and the sub-lethal bacterial reduction was 1.80 log CFU/mL,when compared to the reduction of 0.63 log CFU/mL and the sub-lethal bacterial reduction of 0.05 log CFU/mL(P<0.05) after ultrasonic treatment only. Scanning electron microscopy (SEM) results showed that electrolyzed water combined with ultrasonic treatment had obvious destructive effect on the cell structure of V.parahaemolyticus. The protein leakage of V.parahaemolyticus detected by bicinchoninic acid (BCA) were 226.596 μg/mL, respectively, and difference was significant (P<0.05). Flow cytometry analysis showed that the cells became smaller and the change in particle size increased. In summary, acidic electrolyzed water combined with ultrasound could be more effective in reducing V.parahaemolyticus, the physiological response changes, protein leakage and changes in the physiological states, when compared with acidic electrolyzed water or ultrasound alone. The combination of acidic electrolyzed water and ultrasound could be an new technique to reduce the risk of V.parahaemolyticus.

Abstract:We examined 283 wild Takifugu xanthopterus samples from the East China Sea to investigate the infection of Anisakis. It was found that the infection of Anisakis in T. xanthopterus was the highest in November. In situ photographing of the infected tissue of T. xanthopterus showed that the highest infection rate was as high as 60% in the liver and average infection intensity in the liver is 3 anisakises per fish. Identification by mitochondrial DNA molecules and morphologic features, the parasite of T. xanthopterus is Anisakis pegreffii. LC-MS/MS showed that the content of TTX in Anisakis was 425 ng/g. This is the first time that an anomalous nematode parasitic in T. xanthopterus has been found to have a tetrodotoxin.

Abstract:Euphausia superba lives in an extremely cold environment and its unique proteinase plays a key role in maintaining its metabolic reactions at low temperature. Its carboxypeptidase, as a main and key proteinase, was investigated in this research and it provided support for its further basic research and commercial application. Carboxypeptidase from E. superba was extracted first with buffer solution and then purified respectively with ammonium sulfate, DEAE-agarose gel FF anion chromatography and Sephadex G-100 gel chromatography. The results of SDS-PAGE showed its molecular weight was about 30 ku. Aspects such as optimal temperature, optimal pH, thermal stability, activations and inhibitions allowed an in-depth understanding of the enzymatic properties of carboxypeptidase from E. superba. Its optimal temperature was 30℃ and optimal pH was 8.0. The low thermal stability resulted in a significant diminishing of enzyme vitality after two hours of autolysis, even at 4℃. Ni²⁺, Mn²⁺, Zn²⁺ and Mg²⁺ increased the carboxypeptidase activity and their activations became more significant from left to right. Ca²⁺, Fe³⁺ and Cu²⁺ inhibited its enzymatic activity and Cu²⁺ was the strongest inhibitory. DTT and β -mercaptoethanol, inhibitors of thiol modification, showed inhibitory on the carboxypeptidase. It indicated that there were disulfide bonds in its active center. Metalloproteinase inhibitors EDTA and 1,10-phenanthroline had significant inhibitory on its enzymatic activity, which was similar to the characteristics of metalloproteinase,and serine protease inhibitor PMSF didn't show significant effect on its activity. The kinetic constants of K_m and V_max were revealed at 0.005 9 mg/mL and 4.909 1 U/min respectively with hippuryl-L-phenylalanine as a substrate.

Abstract:The impingement quick-freezing equipment has higher freezing speed and lower dry loss, but its high speed impinging jet also makes the flow field in the heat transfer zone of the equipment uneven and the energy efficiency of the equipment relatively low. This paper took shrimps as the research object, using the method of numerical simulation combined with experimental verification. The effects of two air supply modes (unilateral air supply and bilateral air supply) and two load modes (plate load and net load) on the freezing process of shrimps were studied, and the air supply and load mode which made the shrimp freezing process shortest was found. It was found that for shrimp freezing, the flow field velocity on the surface of shrimp can be increased by bilateral air supply and net belt load, which was beneficial to improve the heat transfer efficiency and reduce the freezing time of shrimp. Compared with other air supply and loading methods, the freezing time of shrimp can be shortened by 14% to 25%. The bilateral air supply was helpful to form an eddy current to increase the flow velocity on the lower surface of shrimp at the weak side of the air supply. The net load can avoid the formation of jet "vacuum area" at the junction between the lower side of the shrimp and the net belt and the head of the shrimp. Both of them are helpful to increase the surface air speed of shrimp and shorten the freezing time of shrimp. The faster the freezing speed, the worse the freezing uniformity of shrimp. In this experiment, the maximum temperature difference between inside and outside shrimp appeared in experimental group D (bilateral air supply + net load), and the maximum temperature difference was 13.02℃.

Abstract:Anchoveta (Engraulis ringens) is a small pelagic fish living in the coast of Peru and Chile. Understanding the variations of fishing ground and its relationship with oceanic environmental factors is beneficial to resource development. Based on the anchoveta fisheries data along the Peru coast from 2005 to 2014 and the oceanic environmental data including sea surface temperature (SST), sea surface height (SSH) and chlorophyll-a (Chl.a) derived from satellite remote sensing, the variations of fishing ground and its relationship with oceanic environmental factors in the two fishing seasons (the first:April-July; the second:November-next year January) was analyzed. Results showed that the ranges of optimum oceanic environmental factors had differences in each fishing month. There was a decreasing trend of optimum SST range as month passed in the first fishing season and an increasing trend in the second fishing season. Each fishing month in both fishing seasons nearly had the same optimum SSH range (29 cm to 41cm). Optimum Chl.a range showed a decreasing trend in the first fishing season and an increasing trend in the second fishing season. Empirical cumulative distribution function test suggested that the optimum oceanic environmental ranges in most fishing months could be the indicators of central fishing ground. But there was no certain form of catch per unit effort along these factors. The studies indicated that, to better understand the variations of anchoveta fishing ground, we should emphasize the annual variation of stock dynamics and other changes in the ocean environment should be emphasized.

Abstract:The sword-tip squid is one of the important economic squid resources in the East China Sea. However, the fishery biology characteristics of the feeding ground in the northern East China Sea are still unclear. Based on the samples of the sword-tip squid collected by the trawlers in the northern part of the East China Sea from September 2017 to February 2018 and September 2018 to February 2019, the basic biological traits were studied. Results have shown that the dominant mantle length and body weight group of male individuals are 100-180 mm and 40-160 g(n=309 ind), respectively, and females are 80-160 mm and 40-160 g (n=304 ind), respectively, and there were differences in the mantle length and weight of the male and female individuals over the years. Covariance analysis (ANCOVA) showed that there were significant differences in body weight-mantle length relationship between males over the years (P<0.05), while the female differences were not significant (P>0.05). Male mature length is mainly concentrated on individuals larger than 120 mm, female is large than 140mm, and the tendency of maturation could be seen under a small mantle length. The mantle length and body weight growth rate of female individuals were faster than males, and the weight growth rate of male and female individuals varied greatly from year to year. According to the comprehensive analysis, the populations of the swordtip squid sampled over the past two years were all spawning populations in spring and summer, and the number of larvae in the spawning population in summer of 2018 was large. Therefore, understanding the dynamic biological characteristics of the fisheries of the swordtip squid is the basis of sustainable resource development and fishery management.

Abstract:We compared photos,wound healing rate, scar reduction rate, IL-6, IL-10, TGF-β, etc. in the skin wound healing process of the groups of IG low, medium and high dose enzymolysis products of oyster by animal experiment, and the results are shown as follows:The wound healing rate of the low and high dose groups was higher than that of the two control groups at 6 and 10 days and on the 14th day the healing rate of the low and high dose groups was significantly higher than that of the negative control group(P<0.05); Enzymolysis products of oyster can inhibit the production of inflammatory factor IL-6 and promote IL-10 secretion(P<0.05); The FGF-2 content in the low dose group was higher than the other groups but there was no significant difference (P>0.05), compared with the TGF-β content in the negative control group(P<0.05), the levels of CCND1 in the three dose groups were significantly higher than the two control groups (P>0.05), and the EGF content in the low and high dose groups was significantly higher than that in the other groups(P>0.05); On the 7th day the hydroxyproline content in the low dose group was significantly higher than that in the negative control group (P<0.05), and on the 14th day the hydroxyproline content in the skin tissue was significantly increased in each administration group and low dose group improves scar contraction rate (P<0.05).Enzymolysis products of oyster has accelerated wound healing of soft tissue in mice and has a certain inhibitory effect on superficial scar hyperplasia.