Abstract:β-catenin, a key factor in the Wnt/β-catenin signaling pathway, is involved in gonadal development and differentiation in fish. In this study, the full-length cDNA sequence of β-catenin2 was for the first time cloned from the FFRC strain common carp (Cyprinus carpio) by RACE-PCR, and expression patterns of β-catenin2 in various tissues and in the development of gonad were investigated. The results showed that the full-length cDNA sequence of β-catenin2 was 3 411 bp, encoding 780 amino acids with a predictive molecular weight of 85.52 ku; Quantitative real-time PCR demonstrated that:β-catenin2 mRNA expressions were high in gonads and the expression increased as the gonads developed in the early development stage. Testosterone (T) treatment increased the relative β-catenin2 mRNA expression level at 10 μg/g 24 h treatment in the ovary. The β-catenin2 mRNA expression decreased at 10 μg/g 24 h, 48 h and 50 μg/g 24 h, 48h testosterone treatments in the testis. 17β-estradiol (E2) treatment had no significant effect on the expression level of β-catenin2 mRNA in testis and ovary (P > 0.05). These data suggested that β-catenin2 is an essential protein in gonad early development of C. carpio.

Abstract:In this study, the full-length cDNA of UB-E2 was obtained using RACE technology in Procambarus clarkii. The expression of UB-E2 gene in different tissues and development stages and the expression of UB-E2 and gonadal development after hormone stimulation by 17α-hydroxyprogesterone were studied by RT-PCR. The results showed that the gene has a full-length sequence of 3 943 bp, an open reading frame of 675 bp, encoding 224 amino acids, a relative molecular weight of 23.93 ku, and an isoelectric point of 8.61. Its amino acid sequence from 82 to 219 is unique protein domain of the ubiquitin-conjugating enzyme family. The amino acid sequence alignment showed that UB-E2 gene of Procambarus clarkii had higher homology with arthropod UB-E2 gene. Phylogenetic analysis showed that the UB-E2 gene was clustered with L. vannamei and P. monodon. Quantitative fluorescence results showed that the expression of UB-E2 gene in ovary tissue of Procambarus clarkii was significantly higher than the other tissues (P < 0.05); it was the lowest in the early stage of ovarian development, then it gradually increased, and it began to decline in the late spawning period; 17α-hydroxyprogesterone stimulation results showed that the ovarian development of the experimental group was significantly accelerated, while the UB-E2 gene expression was also significantly increased, ovarian development and UB-E2 gene expression were consistent with 17 α-hydroxyprogesterone stimulated response. It is speculated that UB-E2 gene plays an important role in ovarian development and gametogenesis in Procambarus clarkii. This study will provide a theoretical basis for the molecular regulation of gonad development in Procambarus clarkii.

Abstract:Molecular markers related with spawning traits in shrimps is limited. At present study, vitellogenin (VG) gene of Litopenaeus vannamei was selected for SNP (Single Nucleotide Polymorphism) marker screening on spawning traits (ie. spawn or not & egg number). Direct sequencing of VG gene was used for SNP loci screening. The detected SNP loci were further correlated with spawning traits. The experiment was based on 150 ablated female shrimps and the four domains of VT gene. During the discovered 37 SNP loci, there were 3 missense mutation, 8 synonymous mutation and 26 nonsense mutation. Further analysis found 4 potential SNP loci whose polymorphism information content (PIC) were between 0.31-0.36 indicated their middle standard of PIC. Single-factor ANOVA analysis was used for the reproductive variables (number of spawns, total egg number, average egg number, and egg number per body weight). Only the locus 3 839 showed the significance difference on total egg number and egg number per body weight (P < 0.05), no significance differences were found in the other 3 potential loci.

Abstract:Twelve different diets with four calcium supply levels and three phosphorus supply levels were prepared for an 8-week feeding trial, which was conducted to investigate the effects of dietary calcium and phosphorus levels on growth, body composition and digestive enzyme activities of juvenile discus fish. The result at the end of the experimental showed that:the survival rate significantly reduced with the rise of dietary phosphorus supply. As 0.5% or 1.0% phosphorus supplied, the specific growth rate of weight (SGRW) sharply declined with the rise of dietary calcium level. Without calcium supplementation, the SGRW showed an obvious increase with phosphorus addition, but no significant difference was found between the two groups fed diets with 1.0% and 0.5% phosphorus supply. The specific growth rate of length (SGRL) significantly declined with the rise of dietary calcium supply. Fish fed diet with 1.0% phosphorus and without calcium supplementation showed the highest SGRL value and lowest length/height ratio. Dietary calcium or phosphorus supply showed significant effect on moisture, crude protein, crude fat and ash content of whole fish. Both protease and lipase specific activities of intestinal tract significantly reduced with the rise of dietary calcium supplementation. Individual phosphorus or calcium supply did not affect the specific activity of amylase while an obvious interaction was found between calcium and phosphorus. In presence of 1.0% phosphorus supplied in diets, amylase activity increased first with rising Ca level, followed by a reduction. Dietary calcium and phosphorus levels also showed an interaction on glutamic-pyruvic transaminase (GPT) activity, and individual calcium supplement showed a significant reduction on GPT activity without phosphorus supply. In summary, 0.5% phosphorus added without calcium was optimal for the growth of juvenile S. haraldi.

Abstract:In order to study the characteristics of the differences in the catch specifications, gonad maturity and digestive ability of Eriocheir sinensis during the reproductive migration, samples were collected from 8 sections in the lower reaches of theYangtze River during the migration flood season from October to November 2014, and the biological investigation and digestive enzyme activity were carried out. A total of 261 samples were randomly collected, including 127 female crabs and 134 male crabs. The variation of shell width is 44.46-96.06 mm, with a mean value of (64.28 ±9.45) mm, and the body mass variation is 34.9 -312.9 g, with a mean value of (131.65 ±57.79) g. There was a significant power function correlation between shell width and body weight. The female crab relationship was y=0.000 8x^{2.859 6} (R²=0.9512), and the male crab relationship was y=0.000 4x^{3.031 5}(R²=0.960 1). The variation of gonad index (GSI) was 0.71-10.84,the mean value was 4.94 ±2.59, and the hepatopancreatic index (HSI) was 2.46-20.04,with a mean value of 7.92 ±1.89. The ratio of amylase to activity was 0.02-5.45 U/mg prot, the mean value was (0.84 ±0.76) U/mg prot, and the ratio of lipase to activity was 0.28-1.13 U/g prot, the mean value was (0.68 ±0.14) U/g prot. The activity of trypsin was changed to 117.21-78 897.26 U/mg prot, the mean value was (10 947.64 ±12 663.57) U/mg prot, and the cellulase activity was 0.74-2.59 U/g prot, the mean value was (1.32 ±0.27) U/g prot. The results showed that Eriocheir sinensis had less feeding during migration,the early stage of migration was mainly supplied by the fat stored in the hepatopancreas, while the later feeding intensity gradually increased. On the reproductive migration channel, the size of the adult crabs decreased along the river, and the male crab was generally larger than the female crabs. The hepatopancreas index and the gonadal index showed the variation characteristics, the activity of amylase and trypsin decreased and the activity of cellulase was smaller, but the activity of lipase increased gradually.

Abstract:In order to study the osmoregularatory function of kidney in Scatophagus argus, primary renal cells were treated with hyposmotic, isosmotic and hyperosmotic media for 24 h. The label-free quantitative method was employed in proteomic analysis, and a total of 3,787 proteins were obtained by mass spectrometry. Compared with isotonic group, 14 proteins were significantly expressed in the hypotonic group and 31 in the hyperosmotic group, respectively (Ratio > +/-2 and P < 0.05). Differential expression profiles were analyzed by Gene Ontology (GO) annotations, enrichment analysis and clustering analysis. The proteins associated with cytoskeleton, energy synthesis and protein binding were selected for quantitative detection at mRNA level to confirm changes of renal cells at gene level and protein level. In hyposmotic group, cytoskeleton-related proteins were up-expressed significantly, including tubulin alpha-4A chain, tubulin beta chain, myosin-11 and type I cytoskeletal 18-like. In the hyperosmotic group, significantly expressed proteins were of extracellular matrix, such as fibronectin and collagen. Therefore, it is assumed that after hypo-osmotic stimulation, intracellular osmotic pressure was higher than extracellular osmotic pressure, and the cells expanded immediately, then expressed cytoskeleton related proteins in large quantities, thus affecting other ion channels. Under hyper-osmotic stimulation, the cells were in a state of water loss and morphologic contraction, which affected the adhesion between cells. However, the increase of fn and plod2 showed that the cells were repairing the damaged protein. This study showed changes of protein expression after anisotonic shocks of primary renal cells in Scatophagus argus and may provide references for further studies of osmoregulation.

Abstract:Qingcaosha Reservoir has a special geographic location and supplies daily drinking water to the vast majority of citizens in Shanghai. It is especially important to maintain the stability of the water ecosystem and ensure good water quality. From January 2015 to December 2016, the characteristics of crustacean zooplankton community in Qingcaosha Reservoir were investigated, and the redundancy analysis (RDA) was used to explore the relationship between crustacean zooplankton and environmental factors. Thirty-four species of crustacean zooplankton were identified, of which 18 species were Cladocera and 16 species were copepods. In 2016, the species of crustacean zooplankton increased by 6 species compared to 2015. Bosmina longirostris and Sinocalanus dorrii are four-season dominant species in two years. The average biological density and biomass of crustacean zooplankton in 2016 were (8.7 ±9.1) ind/L, (0.598 3 ±0.692 6) mg/L, and (3.1 ±2.7) ind/L and (0.208 3 ±0.244 6) mg/L in 2015, respectively. From the river area through the transition area to the lake area, its biological density and biomass gradually increase. The RDA ordination map shows that water temperature, nitrate nitrogen, nitrite nitrogen, and permanganate index have significant impacts on crustacean zooplankton.

Abstract:Investigations of phytoplankton community characteristics in the surface and bottom layers of the Dogai Coring Lake were conducted from April 27 to May 6 in 2009. Fifty-eight sampling stations covered the whole lake. Differences in phytoplankton species composition, density, biomass, diversity and distribution of different latitudes or longitudes in the surface and bottom layers of the Dogai Coring Lake were analyzed. The results showed that a total of 121 species of phytoplankton were identified in the surface layer,the dominant species are Nitzschia sp. and Navicula sp.; 189 species in the bottom layer, the dominant species are Nitzschia sp., Navicula sp., Hantzschia sp. and Hantzschia amphioxys. Bacillariophyta is dominant in species numbers by over 60%. The species between the surface and bottom layers are medium dissimilarity. Higher density (68.434×10⁴ cell/L) and biomass (0.819 8 mg/L) of phytoplankton in the bottom layer than the density (8.444×10⁴ cell/L) and biomass (0.102 1 mg/L) in the surface layer, but the phytoplankton diversity index in the bottom layer is lower than the surface. There was a significant difference between the surface layer and the bottom layer (P < 0.05). The results of cluster analysis revealed the structure in the bottom is more simple than that in the surface, but distribution on the different latitudes or longitudes is similar.

Abstract:To explore the effect of fertilization on the water quality of juvenile crab culture ponds, a field experiment was carried out in Chongming, Shanghai from June to October, 2016. Two groups with three replications each were set:(1) unfertilized group and (2) fertilized group. Water temperature(T), dissolved oxygen (DO), pH, chemical oxygen demand(COD_Mn), total phosphorus (TP), phosphate(PO₄^3--P), total nitrogen (TN), nitrate (NO₃^--N), nitrite (NO₂^--N), ammonia nitrogen (NH₄⁺-N), total hardness and chlorophyll a(Chl. a) of headwaters were monitored seasonally. The result indicated that water quality in the ponds had significant seasonal variation. The water quality factors were comparatively steady in June and September. COD_Mn and Chl. a increased significantly in July and August, while the DO decreased markedly. In the end of crab cultivation, most of the water quality factors increased significantly in two groups, but the total hardness and DO decreased greatly. There was no significant difference in T and pH between headwater and pond water (P > 0.05). DO and NO₃^--N of headwater were higher than ponds(P < 0.05). TP,PO₄^3--P, Chl. a and total hardness in unfertilized ponds were lower than fertilized ponds(P < 0.05). The juvenile crab ponds after fertilizing would cause temporary increase of of TN,NH₄⁺-N,NO₂^--N,NO₃^--N and COD_Mn. The study found that the difference of comprehensive benefits of two groups is not obvious. The fertilized group increased the N and P accumulation in pond and then aggravated the water pollution, having no more benefits than unfertilized group. Therefore, non-fertilization is more suitable for ecological cultivation.

Abstract:Using orthogonal table L₂₀(5¹×2⁸) to arrange 5 kinds of horizontal stocking density(50, 100, 170, 260, 340 ind/m²), and 4 simple water quality control measures, including aeration mode, whether to change water, whether to use microbial agents or disinfectants, to carry out indoor aquaculture experiment of Litopenaeus vannamei. By comparing and analyzing the evolution rule of water quality, the specific activity of digestive enzymes and the effect of aquaculture, the effects of indoor aquaculture density and simple water quality control measures of Litopenaeus vannamei were comprehensively explored. The results showed that the stocking density significantly affected the water quality of the aquaculture water, the growth and yield of prawns (P < 0.05), and also the activity of digestive enzymes. The pH, nonionic ammonia nitrogen (NH₃-N_m) and dissolved oxygen (DO) in the pool water decreased with the increase of density, and the nitrogen nitrate (NO₃^--N), active phosphorus (PO₄^3--P) and turbidity increased with the increase of density. The daily average growth value, specific growth rate (SGR) and survival rate of Litopenaeus vannamei decreased with the increase of density. Except trypsin, the activity of pepsin, lipase and amylase decreased with the increase of density. The low stocking density(50-100 ind/m²) was more neat. Continuous aeration can help the transformation of material, improve the water environment and increase the activity and yield of amylase in prawn. The effect of water exchange on aquaculture and water quality is obvious, it can significantly reduce the content of total ammonia nitrogen (TAN), nitrogen nitrate (NO₃^--N) and active phosphorus (PO₄^3--P) and other hydration indexes (P <0.05), and the activity of digestive enzyme in prawns was increased; The regular release of microecological agents significantly increased the activity of trypsin (P < 0.05), which is beneficial to the growth of shrimp, but not obvious in improving water quality. The application of disinfectant can reduce the activity of digestive enzymes in shrimp. Besides dissolved oxygen (DO), it has no obvious effect on improving water quality and raising aquaculture effect. The results showed that under the simple water quality control measures such as continuous aeration, aquaculture 60 d began to exchange 12.5%-25.0% water for every 10d and the release of microecologic agents per 15 d, 50-100 ind/m² is the appropriate stocking density for indoor cement tanks. The results provide a reliable basis for the cultivation of Litopenaeus vannamei in greenhouse cement pond.

Abstract:Biofloc reactor was used as a key unit of RAS (Recirculating Aquaculture System). The effects of different C/N on the wastewater treatment of biofloc reactor were investigated, and four different gradients of C/N ratio(DOC, Dissolved Organic Carbon; DIN, Dissolved Inorganic Nitrogen, C/N=0, 5, 10 and 15) were set. The experimental results showed that:when C/N=0 (without adding carbon source), the efficiencies of nitrogen and phosphorus removal in the reactor were not obvious, and the accumulation of NO^3--N and PO₄^3- appeared. The increase of C/N, the nitrogen and phosphorus removal efficiencies of the reactor were increasing with the rising C/N. The removal efficiency was the best when C/N=15(P < 0.05), and the removal rate (RR) of TN, NO₃^--N and PO₄^3- (RR) were 46.6%, 43.49% and 24.4%, respectively. During the whole experiment, when C/N=0 and C/N=5, the removal efficiencies of SS, TAN and NO₂^--N were significantly higher than that of C/N=10 and C/N=15(P < 0.05). The stability of the reactor gradually became poor with the increasing C/N, and the highest C/N of reactor could be 15. When C/N was 5, the volume index of floc reactor (SVI-30) was sostenuto less than 150 mg/L, and floc expansion did not appear. When 10 ≤ C/N ≤ 15, the stability of the reactor became worse, but it had no effect on the efficiency of nitrogen and phosphorus removal in the reactor. The ORP and DO values were negatively related to the C/N of the reactor, and they can be used as the parameters of the BFT reactor to optimize the process. Overall, the BFT reactor had good water treatment efficiencies on SS, TAN and NO₂^--N under low C/N conditions, when C/N was more than 10, it had a good water treatment performance on TN, NO₃^--N and PO₄^3-, with simultaneous nitrification and denitrification (SND) and phosphorus removal. For BFT reactor used as a key device of RAS, this study can provide reference for further research and application.

Abstract:Robenidine hydrochloride(ROBH) is widely applied in treatment of diseases caused by sporozoan in freshwater aquaculture. In order to provide theoretical guidance for clinical rational administration in the breeding of crucian carp,pharmacokinetics of ROBH in Crucian Carp with body weight of(120 ±10) g was studied following oral administration of different doses (20 mg/kg, 30 mg/kg and 40 mg/kg) at water temperature of (25 ±1)℃. After administration, concentration-time cruves of ROBH in tested tissues of crucian carp exhibitied a "two-peak" pattern. The peak time, the maximum concentration and the area under the concentration-time curve of three doses in blood were as follows:20 mg/kg,T_max=2.3 h,C_max=0.55 μg/kg,AUC=9.35[(mg/L)·h];30 mg/kg,T_max=2.1 h,C_max=0.73 mg/kg,AUC=13.02[(mg/L)·h]; 40 mg/kg,T_max=2.2 h,C_max=1.17 mg/kg, AUC=13.98[(mg/L)·h]. Area under the concentration-time curve value from higher to lower in tested tissues were:kidney,liver,blood and muscle. The lowest rate of elimination was found in muscle, which was followed by blood. The fact that high ROBH concentration and long MRT were identified in kidney and liver suggested some kind of accumulative effect in both of these two tissues. According to the pharmacokinetics of ROBH in muscle, we suggest a withdrawal period of no less than 9 days in crucian carp. What's more, we suggest the withdrawal period can be adjusted properly because it might be influenced significantly by administration dose and temperature. This is the first pharmacokinetics report about ROBH in freshwater fish, which should be valuable in directing the application of ROBH for disease control.

Abstract:To provide some advice for people when they eat pufferfish, the toxicity of wild pufferfish(Takifugu oblongus Bloch) were investigated and compared with the toxicity of artificial feeding pufferfish (Takifugu flavidus; Takifugu obscurus). In this study, 17 pufferfish tissues were randomly selected, next the tissue was extracted by boiling in 2% acetic acid. After centrifugation, the protein of supernatant was removed by ultrafiltration. The toxicity of 17 wild Takifugu oblongus samples was detected by magnetic immunochromatographic test strip prepared by our laboratory. The representative samples were analyzed and compared with mouse bioassay in regard to the toxicity. Our results showed that the toxicity of muscle and testicle was hypotoxicity, ranging between 0-7 μg/g because of individual difference; The toxicity of ovary and liver were in the range of 4-400 μg/g, was strongest toxicity; The tissues of cultured Fugu flavidus and Fugu obscures were non-toxic.

Abstract:From June 2014 to May 2015, 10 sampling stations were set up in the north of Hangzhou Bay. Monthly collections were held by a larvae net. 120 trawls were carried out and 1 972 ind. of Salanx ariakensis were collected. The development of the vertebral column and the appendicular skeleton of the larvae and juveniles of S. ariakensis was described. A series of wild specimens of 9.7-34.2 mm in body length were cleared and stained for both cartilage and bone. The dorsal, anal, pectoral and pelvic fins supports, neural arches and haemal arches were cartilage. The cleithrum, supracleithrum, posttemporal, hypurals, urostyle and uroneural were bone. All the skeletons developed in the following sequence:pectoral girdle, anal fin supports and hypurals, dorsal fin supports, haemal arches and neural arches, pelvic fin supports and epurals. According to the observation,the postcleithrum was absent in S. ariakensis. The number of neural arches was 73, haemal arches was 22, hypurals (including parhypural) was 7, pterygiophore of anal fins was 27 and dorsal fins was 13. This showed that S. ariakensis had the phenomenon of neoteny that the ossification of the skeletal system was not all bone, which was similar to other salangid fishes.

Abstract:Researches have showed that the stable carbon isotope fractionation of fatty acids in piezophilic gram-negative bacteria exhibited regular patterns with growth pressure in the deep sea, however, the connection between isotopic fractionation of fatty acids in gram-positive bacteria and pressure still kept unknown. Therefore, we studied the carbon and hydrogen isotopic fractionation of fatty acids in gram-positive bacteria Bacillus subtilis under 0.1, 10, 20, 30, 40, 50 MPa by culturing the bacterium, extracting lipids and determining two-dimensional compound specific isotope composition. The results showed that:(1) there was a good linear correlation between hydrogen isotopic fractionation of monounsaturated and branched-chain fatty acids and growth pressure (≥ 10 MPa) as the fractionation became much smaller when pressure increased;(2) carbon isotopic fractionation of branched-chain and saturated fatty acids showed good linear correlation with growth pressure (≥ 10 MPa), where the fractionation was getting much smaller as pressure increased. Additionally, δ¹³ C of monounsaturated fatty acids remained stable. The pattern of hydrogen isotopic fractionation may be attributed to the elevated reaction rate resulted from pressure which promoted the efficiency of hydrogen transformed from NADPH to fatty acids, thus, fractionation weakened. As carbon and hydrogen isotopic fractionation was pressure-dependent, therefore, caution must be taken in tracing marine organic matter sources, determining the transportation and cycles of organic matters, especially in studying hadal biogeochemistry, where stable isotopic fractionation is controlled by growth pressure and microorganisms can alter the isotope patterns of organic matters in marine sediments.

Abstract:How to improve the fishermen's social security level is a social common concern. This article analyzed the fishermen comprehensive social security index. Through the interviews and questionnaire investigation about fishermen comprehensive social security performance at Zhangzhou village in Zhejiang Province and Kunpeng village in Guangdong Province, using the fuzzy evaluation method, this article measured the comprehensive performance of the fishermen's social security. We found that:under the same conditions, the fishermen's social security level is higher who attend the fishery cooperatives than those who do not attend the fishery cooperatives; the higher the level of the organization, the fishermen's social security level is higher. Through relevant policies,government should guide fishermen to join the organized groups such as fishermen' scooperatives, this is an effective ways to improve the fishermen's social security performance.

Abstract:With the development of international and domestic social economy, aquaculture is facing new crises and challenges. Bibliometric analysis of aquaculture thematic documents which collected in the core database of Web of Science in 1997 to 2016. The result shows that the global aquatic science literature has entered a stable development in the last 20 years and the highly cited papers are generally in the fluctuating trend. North American and Western European countries have an absolutely advantage in the aquatic discipline. The three most main research directions in the aquaculture is marine freshwater biology, fisheries and environmental ecology. And the cross discipline is the highlight of the development of the aquatic science and other disciplines. University is the main research force of the global aquatic discipline and the coastal city university has a superior geographical advantage. In the last 20 years, China has been in a high-speed development period in the aquatic discipline research, but the high level output of the aquatic discipline is relatively less, and the aquatic discipline achievements need to be improved in the qualitative aspect. The research direction of aquatic products in our country is more focused on biological and chemical research. There is still have room for improvement in our universities compared with other world-class universities in the world.