Abstract:In the present study,female marbled eel(Anguilla marmorata) were induced to develop ovarian maturation by repeated injection of carp pituitaries extract(CPE) and LHRH-A-2. Five in the fifteen randomly selected injected eels were matured,and were in the completely mature stage with the mean GSI of (20.9±5.04)%(the max GSI was 27.3%); five were in the fullgrown stage with the mean GSI of (7.2±2.86)%; five were in the vitellogenic oocytes stage with mean GSI of (2.32±1.5)%;while the controls were in theⅡ stage with the mean GSI of (1.18±0.39)%.The result showed that eels could be induced completely mature by the exogenous hormone management.mRNA levels of pituitary GtH subunits,serum steriod levels,and histology of hepar and alimentary canal of eels in different development stages were examined.Quantitative realtime PCR revealed that mRNA expression levels of GtHα,LHβ and FSHβ subunits increased with the oocytes development and then decreased after the maturation of ovary.The GtHα and LHβ levels decreased with the maturation of ovary,but were still highly expressed.While the FSHβ levels were hardly to be detected in the matured eels.Serum E₂ levels were high in the early stages and rapidly decreased with the development of the ovary; Serum T levels increased during the ovary development,especially at the mature stage.The PAS stain reaction of hepar showed that the glycogen decreased with the ovary development,and the lipid droplets increased significantly.This can be directly attributed to the fact that glycogen in hepatocytes was involved in metabolism of matter and energy in the development of ovary.The histology of stomach and intestine wall showed varying degrees of degeneration during the development of ovary.

Abstract:Immunohistochemical localization of LHR,ER and PR was performed using rabbit antiserum against leuteinizing hormone receptor (LHR or choriogonadotropin receptor CGR),estrogen receptor (ER) and progesterone receptor(PR).The aim of study was to reveal the endocrine mechanism of exogenous gonadotropin (CPE and hCG) inducing oogenesis and oocytes maturation in ovary of Japanese eel.The results showed that the ovary development and oogenesis in Japanese eel displayed very marked changes before and after hormones injection.The histological section showed at the early phase of vitellogenesis stage before hormone treatment,oocytes average diameter is about (220±0.01)μm,ten days after the first injection of the combination of two gonadotropins.It differed from control group,yolk nucleus scattered in the surrounding of nucleus and number of nucleolus increased obviously,about 18-20 nucleoli,and about 8-10 nucleoli in the control group..After the third and fourth hormones treatment,the oocytes entered in the early mid phase and middle phase of vitellogenesis stage and the number yolk granuleus was increased.After the sixth and seventh hormone treatment,the oocytes entered mature stage from midlate phase of vitellogenesis stage,the cytoplasm of oocyte were full of yolk granules,cellular diameter and nuclear diameter were increased,about (570±1.39)μm and (128±1.19)μm,respectively,while no change in the control group.At the same time,the staining results of immunohistochemistry showed that LHR,ER and PR were located on the cytoplasm,nuclear membrane,nucleoplasm,egg envelope and somatic cell.It was worth to note that localization characteristic of the three receptors after the third and furth hormone treatment,LHR immunoreactivity was located mainly in the cytoplasm of somatic cells(follicle cell at inner layer and thecal cell outside)of oocyte and showed strong immunopositive reaction,while ER and PR were located in the nucleus.Those results revealed that the endocrine mechanism of exogenous hormones (LH,FSH and hCG)inducing the development and maturation of oocyte in female eel were as follows:first, LH and hCG bound with LH receptor on the somatic cells,which stimulated somatic cells synthesis and secretion estradiol17β.Then,E₂ bound with its nuclear receptor in oocyte,stimulating growth and development as well as synthesis of yolk granules in the vitellogenesis stage oocyte.In addition,PR might mediate 17αhydroxyprogesterone in the gene effects of oocyte and its final maturation.For the first time,the present study would provide morphological demonstration.

Abstract:In order to explore the potential compensatory growth of S.constricta,the digestion and antioxidant capacity changes of S.constricta during starvation and refeeding were studied in our study.The materials used in our study are 5 specifications of S.constricta collected from Ningde,Fujian Province.The average shell length of the materials are 0.7 cm,1.4 cm,2.0 cm,4.0 cm and 6.0 cm which are marked as N1,N2,N3,N4 and N5 respectively.In the conditions of seawater temperature 8-11 ℃,salinity 20-22 and pH 7.4-7.9,the effects of sixday starvation and subsequent fiveday microalgae refeeding on the digestion and antioxidant capacity of 5 groups of S.constricta were investigated.The activity of the digestive enzymes amylase and cellulase,malondialdehyde(MDA) content and total antioxidant capacity(T-AOC) were measured as indicators using detection kits(Nanjing Jiancheng Bioengineering Institute,China) during starvation and subsequent refeeding.The amylase activity was determined by means of iodinestarch method and the method of carboxymethyl cellulase(CMC) saccharification was used for determining the activity of cellulase.Using thibabituric acid(TBA) method to determine the MDA content and Fe³⁺ deoxidization colorimetry method was used for the determination of T-AOC.The determination of total protein used the Coomassie brilliant blue.Based on the data and results,the potential compensatory growth of S.constricta was preliminarily explored in our study.The results are as follows:the amylase activity and cellulase activity of S.constricta tended to decrease as the individual size grew,but the opposite is true to the TAOC.In the stage of starvation:the amylase activity and cellulase activity of N1 experienced a rapid and sharp decline while N2,N3 and N4 increased to different degrees before decreased,there were no significant differences in the amylase activity and cellulase activity of N5; the MDA content decreased significantly(P<0.05) except N3,the MDA content reduced to the lowest level after the previous twoday or threeday starvation and after that the MDA content began to rise.Refeeding led to a significant(P<0.05) increase in the activities of amylase and cellulase which were higher than the level before starvation in all groups separately from the 1st day to the 4th day.In the initial 3 days of refeeding,the MDA content of N1,N4 and N5 reduced significantly which was less than the content level before starvation(P<0.05).However,there were no significant differences in the total antioxidant capacity in S.constricta of the 5 specifications during the entire experiment(P>0.05).The results of our study indicated that previous sixday starvation and subsequent fiveday refeeding had no significant effect on the antioxidant capacity of S.constricta but could improve their digestion. A reasonable model of starvation and refeeding of S.constricta is suggested to be set to promote the compensatory growth of S.constricta.

Abstract:RNA interference(RNAi)is initiated by doublestranded RNA(dsRNA)and has been used to improve our knowledge of the shrimp immune system.RNAi has also been used on a therapeutic approach for shrimp virus control.Method for dsRNA synthesis on a large scale will facilitate the application of RNAi in farmed shrimp.Kazal proteinase inhibitor(KPI) gene of shrimp Penaeus monodon was used as an example to show a largescale preparation of long doublestranded RNA(>300 nt) in detail by a 2step cloning method.Two commercial vectors pGEMT and pDRIVE were used to construct a dsRNAexpression system,which transformed into RNasedeficient Escherichia coli HT115(DE3).The hairpinRNA consisted of the target forward sequence(494 bp)and a 91base shortened version of its inverted repeat(403 bp)to introduce a loop,no more need for direct cloning of the loop segment.The hairpinexpression vector resulted in largescale dsRNA synthesis,the yield of dsRNA was about 1 mg dsRNA/30 mL bacterial culture,and its cost was approximately one fourth of the cost of same production by using a commercial in vitro transcription kit.A test group of shrimp Penaeus monodon(8 g,12 shrimp each group)was injected intramuscularly in the fourth or fifth abdominal segment with 16 μg dsRNA to investigate the sequence specific RNAi effect on endogenous KPI mRNA expression.The NaCl injected group and GFPdsRNA injected group were used as control.Hemolymph(200 μL)was collected from 3 shrimp at 0 h,6 h,12 h,and 24 h. RT-PCR test showed that KPI expression was completely knockeddown at 24 h.It should be possible to produce industrialscale dsRNA production for shrimp farms by this in vivo transcription method.

Abstract:The fatty acid synthase(FAS)was cloned from liver of gift tilapia(Oreochromis niloticus).The obtained partial cDNA was 557 bp,which encoded 185 amino acids.Compared with other species FAS,the gift tilapia FAS shared 62%-82% identities.To study the FAS activity and gene expression affected by different dietary lipid levels,three groups of different dietary lipid levels(3.71% group,7.67% group and 16.55% group) were set up with the same nitrogen content.After feeding for 90 days,the fish fasted for 48 hours and then the liver FAS activity and FAS mRNA expression level in liver and muscle were studied;Further,the FAS mRNA expression level in liver was examined after refeeding with different lipid level dietary,at 6,12,24,48 hours.Results showed that FAS activity in liver had no significant change with different dietary lipid levels(P>0.05).The expression level of FAS mRNA in liver was significantly higher than that in muscle(P<0.05).However,the expression level of FAS mRNA in both tissues of liver and muscle was significantly declined with the raising of the dietary lipid level(P<0.05).After refeeding for 6 to 48 hours,the expression level of liver FAS mRNA was significantly declined in each group(P<0.05).Those results indicated that the expression level of liver FAS mRNA was significantly higher than that in muscle.The dietary lipid level could inhibit the expression level of FAS mRNA,and the tendency is:the higher lipid level,the more obvious inhibition.After refeeding for 6 to 48 hours,the expression of FAS gene was impeded.

Abstract:Myeloid differentiation factor 88(MyD88),which is considered as a pivot adaptor molecule for signal transduction of all toll-like receptors(TLRs) except TLR3,possesses important function.In this study,degenerate primer pairs were designed from the conserved regions of the Toll-like/IL-1 receptor(TIR) domain of myeloid differentiation factor 88(MyD88).A 351bp length target sequence was amplified by PCR successfully from the spleen cDNA of Chinese soft-shelled turtle(CSST),and is found as the TIR domain of CSST MyD88 as shown by sequence alignment and domain search.Its identity is 72.9%-86%and 77.6%-83.6%respectively at the nucleotide and amino acid levels as compared with the MyD88 TIR domains of other vertebrates(e.g.yellow croca［Pseudosciaena crocea］,chicken).Real-time PCR revealed that mRNA expression of CCST MyD88 in the liver,spleen and kidney increased to varying extent within 48 hours after intramuscular stimulation of CSST by heatinactivated Aermoans hydrophila.In particular, MyD88 expression in the spleen was 6.89 fold higher than that from unstimulated control. When the heart fibroblast cell line of CSST was stimulated by 20 ng LPS,as stimulator,MyD88 expression increased slightly from hour 1 to 8,but significantly at hour 24.This study has laid good foundation for further study on innate immunity of CTTS.

Abstract:To examine the effects of corn gluten meal on lysozyme activity and c-lysozyme gene expression in Fugu obscurus,the fish were fed with diets containing 0%,5%,10%,15% and 20% corn gluten meal in replacement of 0%,7.4%,14.8%,22.2% and 29.6% of conventional fish meal for 60 days,respectively.Lysozyme activities and mRNA levels in the hepatopancreas,head kidney and spleen were examined.The results show that:(1) At the beginning of the experiment,the lysozyme activities of the hepatopancreas,head kidney and spleen were 9.14 U/mg protein,42.12 U/mg protein and 40.49 U/mg protein,respectively.The c-lysozyme mRNA relative expression levels of head kidney and spleen were 3.76 and 3.24 times of the hepatopancreas.(2) Different amounts of corn gluten meal in the diets exerted different effects on the lysozyme activities.The lysozyme activities of hepatopancreas in the 15% and 20% trial groups were significantly lower than that of the control group,and they significantly increased in the 5% and 10% trial groups.In the head kidney,lysozyme activities were significantly enhanced in the 10% trial group,but they significantly reduced in the 15% and 20% trial groups.In the spleen,there were not significant changes on the enzyme activities in the 5% and 10% trial groups,but in the 15% and 20% trial groups,the enzyme activities significantly reduced.(3) Different amounts of corn gluten meals in the diets also resulted in significant changes in c-lysozyme mRNA levels in tissues.In comparison with the control group,the c-lysozyme mRNA expression levels of hepatopancreas significantly reduced in the 15% and 20% trial groups,although they significantly increased in the 5% and 10% trial groups.In the spleen,there were not significant changes on the c-lysozyme mRNA expression levels in the 5% and 10% trial group,but they were significantly lower in the 15% and 20% trial groups than that of the control group.In the head kidney, c-lysozyme mRNA expression levels were significantly enhanced in the 10% trial group,but they significantly reduced in the 15% and 20% trial groups.In a word,the enzyme activities and c-lysozyme mRNA expression levels were peaked in the 10% corn gluten meal group.

Abstract:Antimicrobial peptides not only represent an important component of innate host defense against microbial colonization and a link between innate and adaptive immunity,but also form a foundation for the development of new therapeutic agents.As the most important antimicrobial peptide families in mussel,mytilin and myticin contain many members referred to as isofoms and have the highest abundance in mussel serum,which means these two families play a key role in mussel innate immunity.To investigate the molecular diversity and the sequence characterization of mytilin and myticin from Mytilus coruscus,the cDNA of mytilin and myticin were cloned respectively by PCR method using M.coruscus hemocyte cDNA library as template.Eight deferent mytilin cDNAs and nine deferent myticin cDNAs were cloned from M.coruscus hemocyte cDNA library,respectively.The precursor translated from mytilin cDNA contains a putative signal peptide of 22 residues,a processing peptide sequence of 34 amino acids,and a C-terminal extension of 46 residues rich in acidic residues; while the precursor translated from myticin cDNA contains a putative signal peptide of 20 residues,a processing peptide sequence of 40 amino acids,and a C-terminal extension of 37 residues.Both mytilin and myticin of M.coruscus are characterized by abundant cationic amino acids and eight cysteins which formed four disulfides.Sequence analysis of the coding frame showed that the variation loci of these two kinds of antimicrobial peptide mainly occurred on mature peptide region,which might result from direct interaction of these peptides with the surrounding pathogens in the changing environment and thus become a likely cause of molecular adaptation of certain amino acid sites in mytilin and myticin variants.This study laid the foundation for intensive study on immune mechanisms as well as screening antimicrobial peptide molecules from M.coruscu antimicrobial peptides.

Abstract:A 60 day feeding trial of 3 dietary protein levels (28%,32% and 36%) and 3 dietary lipid levels (5.0%,7.5% and 10.0%) designed with 4 replications was conducted to determine the effects of dietary protein and lipid levels on growth,digestive enzyme activities and muscle composition of juvenile channel catfish［initial body weight:(1.5±0.02)g］.Fish were fed respectively to apparent satiation by 9 experimental diets named P28L10,P32L10,P36L10,P28L7.5,P32L7.5,P36L7.5,P28L5,P32L5 and P36L5 with 4 replications.The results indicated that weight growth rate (WGR) and feed coefficient rate (FCR) were significantly affected by dietary protein and lipid levels or a dietary protein × lipid interaction (P<0.05).WGR and FCR of fish fed the P28L10 diet were the lowest among all the treatments (P<0.05).Growth performance of fish fed diets with 28% protein were lower than that of fish fed higher protein levels (P<0.05);the lowest growth performance was observed in fish fed the P28L10 diet.The highest WGR was obtained in fish fed the P36L7.5 diet;and no obvious differences of WGR were found in fish fed the P36L7.5,P36L10 and P32L7.5 diets (P>0.05).Activities of liverlipase and stomachprotease changed significantly as dietary lipid levels increased (P<0.05).Muscle lipid levels decreased significantly with dietary lipid levels (P<0.05),and muscle protein levels could be influenced by dietary protein and lipid levels.Viscerasomatic index (VSI),mesenteric lipidsomatic index (MSI) and condition factor (CF) together may show that muscle protein and lipid levels could be affected by dietary protein × lipid interaction.In conclusion,this study suggests that growth performance of juvenile channel catfish is improved at a suitable protein/lipid ratio in diet.Fish fed diet containing 32% protein,7.5% lipid and 22.4 mg/kJ P/DE ratio got the best growth performance and the ideal body composition.

Abstract:Channel catfish virus(CCV) is a pathogen of channel catfish.This virus can cause severe hemorrhagic disease in young channel catfish and cause major losses to fish farmers.As no efficacious treatment exists,a vaccine against CCV is essential for prevention and control of this disease.Recently,the baculovirus was described as an attractive gene delivery vehicle and a potential vector for vaccine development.In order to express the membrane protein of the CCV ORF6 gene in insect cells,ORF6 gene was subcloned into baculovirus transfer vector(pFastBac^TM-1).The recombinant plasmid pFastORF6 was identified by restriction enzyme digestion and gene sequencing.DH10Bac containing baculovirus shutter vector(bacmid) and helper vector was transformed with recombinant plasmid pFastORF6.The recombinant bacmid(rBacmidORF6) was identified by blue/white selection and PCR analysis.Then the rBacmidORF6 was transfected into sf9 cells with Cellfectin Reagent and recombinant baculovirus was obtained in sf9 cells,named AC-ORF6.AC-ORF6 was multiplenucleopolyhedrovirus which was observed by electron microscopy in the ultra thin section of infected sf9 cells.After AC-ORF6 infection,the recombinant CCV ORF6 protein was characterized by indirect immunofluorescence assay and Western-blotting.The results showed that ORF6 protein was expressed in sf9 cells and had a molecular mass of 16 ku.This study will provide useful basis for the subunit CCV vaccine development in the future.

Abstract:The physicochemical properties of most food allergens confer stability to the proteolytic in the digestive tract,which increases the probability of reaching the intestinal mucosa,where absorption and interaction with the immune system can occur.Stability in simulated gastric fluid is supposed to be an important parameter for the estimation of food allergenicity.The digestive stability of a major fish allergen(parvalbumin,PV) and nonallergenic proteins from the muscle of crucian carp (Carassius auratus cuvieri) and silver carp(Hypophthalmichthys molitrix) in a standard simulated gastric fluid(SGF) and simulated intestinal fluid(SIF) digestion assay system was compared.Proteinases including pepsin,trypsin and chymotrypsin from porcine were used to simulate digestive proteinases from human.The results were evaluated by means of Tricine-sodium dodecyl sulfatepolyacrylamide gel electrophoresis(Tricine-SDS-PAGE) and Western-blot.Fish PV was purified to homogeneity by 70%-100%ammonium sulfate fractionation and DEAESepharose following heat treatment and a protein with molecular weight of approximately 10 ku was finally obtained.In SGF assay of purified crucian carp PV and silver carp PV,similar results were obtained,the original PV band was almost completely degraded within 60 min and some stable peptide fragments were observed.In SIF assay of purified PV,both trypsin and chymotrypsin could not degrade PV effectively in 4 h.In SGF digestion on fish sarcoplasmi proteins,nonallergenic proteins were rapidly degraded within a short period of time,while the digestion of PV was prolonged to some degree.Western-blot analysis indicated that the polyclonal antibody against silver carp PV can specifically detect the PV and it degraded products.In conclusion,our present results indicate that fish PV is more resistant to proteinase digestion than nonallergenic proteins and pepsin treatment is more effective than trypsin and chymotrypsin in reducing the hypersensitivity.It should be remembered that our present study only measured the antigenicity which may not completely equate to allergenicity.Thus,to further evaluate the allergenicity alteration of PV after proteinase treatment,experiments such as the release of histamine from basophiles and skin prick test are required.In addition,the amount of undigested PVs that has to persist in gastrointestinal digestion to induce food allergy is also needed to be studied.

Abstract:Biological reference points (BRPs) are often used as the benchmark in quantifying management objectives and determining the status of fisheries stocks.In general,there are two groups of BRPs,fishingmortalitybased and biomassbased.For fishingmortalitybased or biomassbased BRPs,there are target reference point (TRP),limit reference point (LRP) and threshold reference points (ThRP).Target reference points are used to quantify the management goals.Typical target BRPs include target biomass B_msy,target spawning stock biomass S_msy、SSB_35%、SSB_40%,target fishing mortality F_msy and its proxies such as F_max,F_0.1,F_med,F_35%,F_40%.These represent ideal or optimal levels of stock biomass and fishing mortality that are sustainable. The LRPs are used to ensure that fishing mortality is not too high to overfish populations and that stock biomass is not too low to sustain itself,and often include F_msy, F_max,F_0.1,F_crash,F_20%,and B_loss.Threshold reference points usually have values between the TRPs and LRPs and act as a warning or precautionary indicator before the fisheries reach the LRPs.The BRPs are usually estimated from dynamic pool models,production models and stockrecruitment models,and are often incorporated into a harvest control rule (HCR) in fisheries management.Large uncertainty is often associated with BRPs,which may result from errors in key life history parameters and variability in the ecosystem.In this study,using tuna fisheries as an example,we comprehensively reviewed the development and application of BRPs in fisheries management.We also discussed the development of BRPs and relevant HCR for the management of inshore fisheries in China.

Abstract:In order to study flavor determination and evaluation technology of shrimp flavorings,the fresh Penaeus vannamei shrimphead was used as raw materials,and processing by enzymatic hydrolysis and Maillard reaction(MR) techniques,we obtained an flavoring which has better flavor.Then Solid Phase MicroExtractionGas ChromatographyMass Spectrometry(SPME-GC-MS) was adopted to determine the characteristic volatile flavors,the different effects of the two processings were discussed.The results indicated that there were 57 and 63 kinds of volatile compounds identified respectively by comparing their mass spectra with those contained in the NIST mass spectral database.Among these compounds,most of them were hydrocarbons,alcohols,aldehydes,kotones,nitric compounds and sulfuric compounds.They cooperate with each other to make up the specific aroma of shrimp flavor.The results also indicated pyrazines were the primary constituents of shrimp flavorings.Compare the determination results of samples before and after Maillard reaction,there were 17 and 21 kinds in the two samples,and the contents were 40.58% and 47.83% respectively.It is also showed that the flavor development function of Maillard reaction is significant by this study.Therefore,the product manufactured by Maillard reaction can be used not only as a seasoning directly,but also can be used as the basic raw material to functional combined seasoning for further coordination.By this means,the useful range can be expanded in food flavoring industry.

Abstract:An optimal culture structure of shellfishfishalgae and its ecological environment bioremediation system were established and studied in the paper.The experimental study was carried out in a semienclosed sea area of 33.3 hm² by net fence.The system includes three different functions culture areas:the shellfish and pearl culture area,the fish net cage culture area and the macroalgae culture area.The interculture of fish,shellfish and macro algae and pearl rearing were implemented in the demonstrative sea area.After 10 months of optimal structure culture and ecological environment bioremediation control,the water quality and biological environment of the demonstrative sea area were obviously improved.The transparency of the demonstrative sea area was significantly higher than its adjacent sea area(P<0.05),while the suspended substance content was significantly lower than its adjacent sea area(P<0.05);The concentration of total nitrogen and total phosphorus in the demonstrative sea area was increased with the cultural period of time,the high peak was in September,then it was decreased with the further cultural period of time; The biomass of plankton in the demonstrative sea area was increased with the cultural period of time,and significantly higher than its adjacent sea area(P<0.05).The marine aquaculture organisms in the demonstrative sea area grew well,the output of fishes,macroalgae and pearls respectively reached 21 365 kg,3 091.3 kg and 33.5 kg.The survival rate of pearl oyster(Pinctada martensii) reached 73.9%,the remained nucleus ratio of pearl oyster reached 49.9%,the percentage of high grade pearl was 13.7%,and the pearl layer thickness was 472 μm on average.It can be concluded that the quality of pearl was significantly improved.The photosynthetic energy efficiency reached 0.20% in the demonstrative sea area,the total energy conversion efficiency was 34.58%,the total energy consumption per unit of net yield was 2.891 9 MJ/kg.

Abstract:Using artificial spawning and dry insemination,experiments on interspecific hybridization within females of Spinibarbus sinensis and Spinibarbus denticulatus and males of S.sinensis and S.denticulatus and Spinibarbus caldwelli of Spinibarbus were conducted.Comparisions of egg membrane diameter,fertilization rate,hatching rate,hatching time,abnormality rate,early larvae morphological characters and survival rate were made at temperature of (27±0.5)℃.Meanwhile the embryonic development and abnormal phenomena of hybrid were observed.The results showed that there was no distinct difference on egg membrane diameter between the crossbreeding and the oosperm of the female parent of S.sinensis(P<0.05).There was no distinct difference on egg membrane diameter between the crossbreeding and the oosperm of the female parent of S.denticulatus at multicellular stage,but there was distinct difference on egg membrane diameter between the hybrid of S.denticulatus ♀×S.sinensis ♂ and the oosperm of the female parent of S.denticulatus at otolithes appearance stage(P<0.05).The fertilization rate and hatching time of hybrid were not significantly different,but the abnormal rates were significantly higher compared to their mother’s(P<0.05).The hatching rates of crossbreeding of S.sinensis were high and not significantly different compared to their mother’s(P<0.05).The hatching rate of S.denticulatus ♀×S.sinensis ♂ was not distinctly different,but the hatching rate of S.denticulatus♀ ×S.caldwelli ♂was significantly lower compared to their mother’s(P<0.05).There was high death rate stage in the early larvae development of crossbreeding of S.sinensis,and the survival rates were significantly lower than their mother’s(P<0.05).There were characteristics partly similar to the female parent or male parent for hybrids of crossbreeding of S.sinensis and S.denticulatus ♀×S.caldwelli ♂.It showed preliminarily that it was feasible for the interspecific hybridization of three species of Spinibarbus.

Abstract:Sarotherodon melanotheron, Oreochromis niloticus, Israel red tilapia and Oreochromis aureus were used as parents which produced nine offspring by selfed and diallel crossing.After trials of lethal salt tolerance,median lethal salinity and gradual salt-tolerance domestication,differences of salt-tolerance ecological characteristics were compared and analyzed.The major results were:(1) There were greatest significant differences(P<0.01) of MST, ST₅₀ and survival rate between S.melanotheron and the other 8 tilapias,S.melanotheron’s MST was (9.24±1.353)h,ST₅₀ was (6.20±1.235)h,theoretic MLS₉₆ was 30.2,observed MLS₉₆ was 31.2,these values were far higher than those of the other 8 tilapias.(2) 9 tilapias might be divided into four groups based on their salt tolerance:the first group was S.melanotheron which had the strongest salt-tolerance among nine tilapias;the second group was Israel red tilapia and O.niloticus♀×O.aureus♂ which had strong salt-tolerance and had positive residual values;the third group was O.aureus,O.niloticus♀×Israel red tilapia ♂,Israel red tilapia♀× O.niloticus, ♂O.niloticus♀×O.aureus♂, and O.aureus♀×O.niloticus♂ which had stronger salt-tolerance and had negative residual values;the fourth group was O.niloticus which had inferior salttolerance.(3) When domesticated gradually salinity rising, S.melanotheron’s mortality rose from 0 to 30%,then it rose slowly,there was a fast rising during the fourteenth day to fifteenth day,and then it rose slow too,50%mortality occured on the eleventh day which had a 32.8 salinity,all trial fish dead on the thirtyninth day,which salinity was 102.The regress relation between mortality and domestication time of S.melanotheron was LnY=3.430+0.640X(R²=0.976).(4) S.melanotheron would be a perfect parent which bred new seed of salt tolerance.

Abstract:600 sea urchins Strongylocentrotus intermedius were randomly chosen from 20 families and the gonad wet weight,gonad index,gonad moisture and fatty acid composition were measured and then analyzed.The results showed that gonad wet weight and gonad index were both significantly different among families(P<0.01),but not between genders,and there was a large gonad yield variance in the measured population; The gonad color of S.intermedius lies between bright yellow and bright orange red,the color was quantified by CIEL^*a^*b^* standard and then ANOVAs were conducted.L^* and a^* components were of no difference among families,but b^* component,ΔE₁ (light yellow) and ΔE₂ (light orangeyellow) were all significantly different among families.The L^*a^*b^* components and the two ΔE_s of the female were superior to male; The family and gender had significant effects on gonad moisture(P<0.01 and P<0.05,respectively); There were relatively high EPA(12.11±2.65)% and AA (10.27±3.40)% contents,but lower DHA(0.49±0.64)% content (with high variation of 130.77%) in the gonad total lipid of S.intermedius.The HUFA was significantly different among families(P<0.01),but there was a significant difference of AA between genders only with the male higher than female.The present study indicated that sex and family selection should be conducted to achieve the goal of the gonad enhancement.

Abstract:To advance the understanding of the diet of the greater lizardfish,Saurida tumbil(Bloch,1795) and its monthly and ontogenetic variations,an annual research was conducted from October 2008 to September 2009.Stomachs of 749 greater lizardfish,ranging in size from 124 mm to 375 mm in standard length(SL),were sampled monthly in the Beibu Gulf of the South China Sea,and analysis of their stomach contents showed Decapterus maruadsi to be the primary prey components of the diet,averaging 9.7%by number,55.5%by weight and 34.9%by percentage of Index of Relative Importance(IRI).Small benthic fish,Bregmaceros rarisquamosus and pelagic fish, Thryssa setirostris and Leiognathus riviulatus,with IRI percentages of 26.6%,4.3% and 2.5%,respectively were also relatively essential in the diet of this fish,whereas the other species of prey were only present in comparatively lower percentages.The research findings revealed that the mean repletion index and mean maturity coefficient varied considerably by month,while trophic diversity,calculated by Brillouin index H_z, proved to be relatively consistent throughout the year. Mean repletion index(RI) was highest(RI=7.61%) at the stage of Ⅵ-Ⅱ indicating that this group of greater lizardfish that reverted from Stage Ⅵ to StageⅡ increased their food input to compensate for energy loss during reproduction.On the other hand,the proportion of empty stomachs reached its peak with 61.5% while mean RI reached the second highest position with 5.98% at Stage Ⅴ,indicating that during the reproduction periods from March to April,and in June and November,greater lizardfish ceased feeding until digestion of the prior meal was completed or near completion.The 12 SL classes demonstrated significant differences with respect to prey weight but showed relative consistency in prey numbers.The tendency of mean prey weight increased the body size following with the improvement of the feeding organs and swimming ability of greater lizardfish.Using PRIMER 5.2 software,the cluster analysis,based on IRI values for the above SL classes,showed that the feeding habits of greater lizardfish were generally homogeneous among different sizes,particularly among the 136-255 mm SL classes,with similarities of more than 60%.In conclusion,the diet of greater lizardfish,Saurida tumbil varied significantly by month and ontogenetic development.These findings may assist in the development and improvement of marine ecosystem modeling for the Beibu Gulf,South China Sea.

Abstract:To investigate the effect of high temperature stress on growth performance and activities of antioxidant enzymes in juvenile olive flounder Paralichthys olivaceus,the survival,growth,feeding,activities of superoxide dismutase (SOD) and catalase(CAT) of olive flounder at different temperatures (25 ℃,28 ℃,30 ℃,31 ℃ and 32 ℃)were compared.The results showed that the survival rate of juvenile olive flounder was 100%at the temperatures of 25 ℃,28 ℃,and 30 ℃,and the survival rate was 95%±1.18% at the temperature of 31 ℃.Nevertheless,the survival rate was (20.83%±2.20%) at the temperature of 32 ℃.The water temperature significantly affected the specific growth rate(SGR),feeding rate(FR) as well as feed conversion efficiency(FCE) of juveniles.A quadratic regression was fit to describe the relationship between the SGR,FR,FCE and the water temperature(SGR:R²=0.93;FR:R²=0.90;FCE:R²=0.86;P<0.01).The SGR,FR and FCE reduced with increasing water temperature in the temperature range of 25-32 ℃. Moreover,SOD and CAT activities in liver were measured under high temperature stress and the two critical antioxidant enzymes were also significantly affected by high water temperature.The activities of SOD and CAT declined with the increasing water temperature.This study indicated that the temperature of 32 ℃ may be the upper limit for olive flounder,and the high water temperature has a significant effect on growth performance and activities of antioxidant enzymes of olive flounder.Our results would be good references for genetic breeding and healthy culture of olive flounder.