Abstract:The changes in physiochemical properties of myofibrillar protein from crucian carp during heattreatment were studied through the tests of turbidity,viscosity,Ca²⁺-ATPase activity,total sulfhydryl content and a SDS-PAGE study.Research on changes in physicochemical properties of myofibrillar protein during heattreatment can help to understand the thermal denaturation of it and provide practical information for crucian carp muscle processing,so as to promote the utilization of huge amount of freshwater fish resources in China.The results showed that turbidity increased as temperature rose.Turbidity did not show a significant increase from 20 to 34 ℃.With increasing temperature from 36 to 70 ℃,turbidity increased significantly and three peaks of change rate was observed at 36,42 and 48 ℃.No significant shifts were detected when the temperature became above 70 ℃; Viscosity declined from 20 to 47 ℃,and two peaks of change rate were observed at 35 and 47 ℃.No significant shifts were detected when the temperature became above 47 ℃.Ca²⁺-ATPase activity decreased from 28 to 40 ℃,at the first stage(28-34 ℃),Ca²⁺-ATPase activity decreased slowly,then,from 34 to 40 ℃,Ca²⁺-ATPase activity decreased significantly and one peak of change rate was observed at 36 ℃.At 40 ℃ Ca²⁺-ATPase activity reduced to zero.Sulphydryl content decreased in ranges 20 to 28 ℃ and 40 to 68 ℃ and kept a certain value at 68 ℃ with a slight increase from 28 to 40 ℃.Electrophoretic analysis indicated high temperature(≥40 ℃)induced disulfide bonding between myosin chains and other proteins and formed macromolecular substances.

Abstract:Effects of salinity on activity of Na⁺/K⁺-ATPase in gill,kidney and liver of Oplegnathus fasciatus were studied.The activity of Na⁺/K⁺-ATPase changed when Oplegnathus fasciatus was treated with different salinity of 8,18,28,38 and 48.Following fish treated with low salinity(8 and 18),the activity of Na⁺/K⁺-ATPase in gill increased a little during first 6 h,then it dropped and reached minimum at 24 h.Afterwards,it increased again.As to fish treated with high salinity of 38 and 48,the activity of Na⁺/K⁺-ATPase in gill decreased a little during first 6 h,then increased and reached maximum at 24 h.After that,it dropped slowly again,and had no significant difference from that in control groups at 96 h(P>0.05).The activity of Na⁺/K⁺-ATPase in kidney of all treated groups increased a little during first 6 h.After that,it dropped gradually and reached minimum at 24 h.Then,it increased again.The activity of Na⁺/K⁺-ATPase in liver had similar trend with that in kidney when treated with the lowest salinity of 8.But as to juvenile in other 3 salinity groups,the activity of Na⁺/K⁺-ATPase decreased gradually and reached minimum at 24 h,then it increased again.Our result indicated that Oplegnathus fasciatus is a highly euryhaline fish and a very strong osmoregulator,salinity with the range from 18 to 38 had only a little influence on the activity of Na⁺/K⁺-ATPase in gill,kidney and liver.But extreme salinity(8 and 48)could exert a more obvious influence.And change of salinity had more influence on the activity of Na⁺/K⁺-ATPase in gill and liver than that in kidney.

Abstract:To investigate the histological structure and seasonal variation of the pituitary from Trionyx sinensis,the histological structure of T.sinensis pituitary in September and January was observed under light microscope and electron microscope.HE,PAF-AB-PAS-OG staining and immunohistochemical study were undertaken using different dyes or antisera.From the anatomical point of view,the pituitary of T.sinensis was composed of two lobes:the adenohypophysis and the neurohypophysis.It was functionally linked to the hypothalamus by the pituitary stalk.Adenohypophysis was composed by pars tuberalis and pars distalis,but pars intermedia was absent in the T.sinensis.Pars distalis could be divided into head lobe and tail lobe,and the former was larger than the latter.The neurohypophysis was small and fingerlike extending into the pars distalis.Different cells of adenohypophysis were divided into three cells of eosinocyte,basicytes and chromophobe cells.The shape and distribution of those kinds were different obviously.The eosinocytes were mainly located in the central region of pars distalis while the basicyte in the surrounding area,eosinocytes were generally smaller than basicyte and possess a round and sidelined nucleus,the basicyte were bigger and possess a central nucleus; the chromophobe cells and adrenocorticotropic cells were densely distributed in the pars tuberalis and sporadically distributed in the pars distalis.The quantity of somatotrophs and gonadotrophs in breeding season was higher than that in winter while other cells did not change significantly.Under electron microscope,the cells in adenohypophysis were divided into six categories of somatotrophs,gonadotrophs,thyrotrophsprolactin cells,adrenocorticotropic cells,adrenocorticotropic cells and chromophobe cells according to the cell size,shape of nucleolus and secretory granules in the cytoplasm.The quantity of secretory granules in cytoplasm of somatotrophs and gonadotrophs changed significantly in summer and winter.

Abstract:Cephalopods is one of the most important sources of protein for human.Its reproductive system is an important part for cephalopods,not only is considered as the basis of biological study and the focus of reproductive biology,but also plays an important role in the taxonomy.For females,there are such remarkable differences as the oviduct and oviducal gland among Ommastrephids,Myopsids,Sepioids and Octopods.Seminal receptacle of Decapodiformes is located in buccal mass,but that of Octopodiformes on oviducal gland.Bursa copulatrix is one special organ in subfamily Sepiolinae to be considered as a certain role in taxonomy for genus Epietta.For males,hectocotylus is an important taxonomy characteristic and there are some differences in their locations and structures among different cephalopods.Copulatory apparatus is a special structure in hectocotylus,whose usage is also considered.The majority of cephalopods with complex spermatophore of which ejaculatory apparatus,connective complex and sperm mass are considered of certain significance at taxonomy in family Histioteuthidae,but major cephalopods with simple spermatophore is generally called sperm packet.

Abstract:Swimming performance is considered a critical character determining survival in many fishes in the natural circumstances.For many fishes,swimming is the main way to avoid the attack from their predators,obtain food,find a mate,and so on.Experimental tests are important means for measuring the swimming performance of fish.Many influence factors on fish’s swimming performance have been studied extensively.However,important as they are,no study has been carried out on the influence of acclimation time period, acclimation flow velocity and acceleration flow velocity on fish’s swimming performance.Experimental results measured under different acclimation conditions are incomparable and are always open to question.In this paper,the effects of acclimation flow velocity,acclimation time period,acceleration time period and testing flow velocity on the sustained swimming time of Sciaenops ocellatus and Acanthopagrus schlegel were studied.The Uniform Design method was used in the experiments where a 4-factor and 8-level design was applied to Sciaenops ocellatus tests and a 4-factor and 7-level design was applied to Acanthopagrus schlegel tests.The experimental results and theoretical analysis showed that the acceleration time period has greater effect on the sustained swimming time under stronger flow velocities than that under slower flow velocities.The influence of acceleration time period on the sustained swimming time is also related to fish species,fish size,current velocity,etc.It is suggested that the maximal acclimation velocity should be limited to 1.5 BL/s to avoid significant energy loss of testing fish.The acclimation time is recommended not to exceed 60 min though a longer time may be better for the fish to adjust itself to a new environment.A wellfitted powerfunction relationship was found between the sustained swimming time and the testing flow velocities.The sustained swimming time decreases significantly as the flow velocity increases.The conclusions obtained in this paper may give an important guidance to the testing approaches of fish’s swimming performance.

Abstract:Short-period fluctuations in ambient temperature have a major impact on the growth and energy metabolism of fish.Under indoor controlled conditions,the growth and energy distribution of the brown flounder(Paralichthys olivaceus)juveniles undergoing the cycles of high temperatureoptimal temperature operation were investigated.During a single10day cycle,the 20 ℃ acclimated juvenile brown flounder were cultured at high temperature(26.5 ℃)for different days as follows:0 d(H₀),2 d(H₂),4 d(H₄),6 d(H₆),and 8 d(H₈),and then maintained at 20 ℃(optimal temperature)for the remaining days.The fish were stocked in five recirculating systems and each system was equipped with three aquaria(80 cm×50 cm×35 cm,about 140 L).Aeration was continually provided to keep the dissolved oxygen content above 5.5 mg/L.The salinity of the seawater was 30 and pH was 7.5±0.3.A photoperiod of 14 L∶10 D was adopted during the experiment.The fish were cultured for 4 cycles(40 d)and at the end of the experiment period,the body weight of fish which experienced different periods of high temperature exposure expressed in dry mass,wet mass,protein,and energy were all significantly lower than those of control group(H₀).The lipid contents of the final fish which experienced high temperature were significantly higher than those of H₀.Similar trend was observed in the protein contents of the final fish,except that H₆ was slightly lower than H₀.Through the experimental period,less feed ingestion and smaller fraction of energy allocated to growth mainly depressed the growth of fish which experienced different periods of high temperature exposure.The feed ingestion of the fish which experienced different periods of high temperature exposure was slightly lower than that of the controls,but the feeding rate,digestibility and food conversion efficiency were not significantly different from those of the control group.The energy allocated to growth in H₂, H₄,and H₆ was not significantly different from H₀.The highest proportion of energy lost in feces and excretion appeared in H₄ and H₆ respectively.The energy distribution in the growth in H₈ was significantly lower than other treatments and its proportion of metabolic energy consumption was significantly higher than other treatments.The daily unit body weight energy ingestion of the fish which experienced different periods of high temperature exposure were was significantly different from H₀,but the energy allocated to growth was significantly lower than that of H₀.It could be concluded that the complete and over compensatory growth can not be achieved in similar highoptimal temperature operation.The above results indicated that the juvenile brown flounder showed poor flexibility to the cycle of hightemperatureoptimumtemperature operation and temperature fluctuation would impact their growth.

Abstract:A feeding trial was conducted to estimate the quantitative requirement of dietary methionine in largemouth bass［initial body weight (37.88±0.40) g］.Six isonitrogenous and isoenergetic diets(D1D6)were formulated to contain 44.39% crude protein,0.30% cystine,19.81 kJ/g gross energy using plant protein and crystalline amino acids as the primary protein source to simulate the indispensable amino acid profile of largemouth bass muscle except for methionine under investigation.Six graded levels of methionine(0.61%,0.83%,0.98%,1.21%,1.42%,and 1.59%,respectively)at about 0.2% increment were achieved by adding zeincoated crystalline Lmethionine at the expense of zeincoated crystalline glycine.Each diet was randomly assigned to triplicate tanks of 200L capacity and 18 tanks were connected to a freshwaterflowing and airaerated system in an aquiculture laboratory.In each tank,25 fish were fed by hand twice daily(8:30 and 15:30)to apparent satiation for 66 days.Water temperature was maintained at (27±1)℃ and dissolved oxygen content kept about 6 mg/L.Light cycle was controlled under 12∶12 h.At the end of the trial,data analysis showed that specific growth rate(SGR),feed efficiency rate(FER),protein efficiency rate(PER),protein deposition rate(PDR)increased with increasing dietary methionine levels from 0.61% to 1.21%(P<0.05)and thereafter showed a declining tendency.The crude protein contents of whole body and muscle were significantly affected(P<0.05)by dietary methionine levels,while moisture,crude lipid and crude ash contents showed no significant differences(P>0.05).The hepatosomatic index and viscerosomatic index of fish fed D1 diet(0.61% methionine)were significantly higher than those of fish fed the other diets(P<0.05).The serum lysozyme activity,phagocytosis activity and respiratory burst activity of head kidney leucocyte were significantly(P<0.05)affected by dietary methionine levels,which indicated dietary methionine level would also exert an effect on nonspecific immunity in largemouth bass.A quadratic regression analysis about specific growth rate(SGR)against dietary methinine level showed that the optimum dietary methinine requirement of largemouth bass was 1.22% of dry diet(corresponding to 2.75% of dietary crude protein containing 0.68% cystine).The present research may be helpful to formulating practical feed for largemouth bass.

Abstract:In present study,genetic differentiation of the Chinese shrimp Fenneropenaeus chinensis between cultured(21 individuals)and wild populations(14 individuals,sequences were downloaded from the GenBank)was investigated using the sequence of mitochondrial control region(CR).Four individuals of theF.merguiensis were chosen as the outgroup during the phylogenetic analysis in this study.Sequences were edited and aligned using DNA Star software and refined manually.Genetic diversity indices such as number of haplotypes,polymorphic sites,transitions,transversions,and indels were obtained using the program ARLEQUIN(Ver. 3.0).Haplotype diversity(h)and nucleotide diversity(л)were calculated with DNASP 4.0.The nucleotide compositions and the average distances between populations and within population were calculated with MEGA 4.0.The Network software was used to draw the minimum spanning tree based on the haplotype data.The results were as follows:the A+T content was higher than the G+C content in both the populations,but the G+C content was a little lower in the cultured population.The results indicated genetic divergence existed between the 2 populations based on the 563 bp sequences.The gene diversity of the wild population(0.967 2)was a little higher than the cultured population(0.938 0).There was no shared haplotype between the 2 populations.The ratio of transitions/transversions of the wild populations and nucleotide diversity were 3.5 and 0.010 6 respectively while they were 4.0 and 0.009 4 for the cultured population.The nucleotide diversity of the wild population was a little higher than cultured population.The K2P distance was 0.010 8 between the 2 populations,0.010 7 in the wild population and 0.009 5 in the cultured population.Both the NJ phylogenetic tree and the haplotype minimum spanning tree showed no significant genealogical structure.The exact test of population differentiation showed that the 2 populations were significantly different(P=0.000 9).The F_ST value between the populations was 0.069 8(P=0.00),which indicated that the difference between 2 populations was significant.This may indicate that some alleles were lost during the aquaculture.

Abstract:We studied the possible role that marine microalgae may play during the outbreaks of acute viral necrobiotic disease(AVND)of cultured zhikong scallops(Chlamys farreri).In order to elucidate the possibility of marine microalgae carrying AVNV(acute viral necrobiotic disease virus),seventeen species of microalgae were co-cultured with pure AVNV solution and were assayed daily by PCR to study whether they could carry AVNV. Further experiments were conducted to investigate whether the virus carried by microalgae could reinfect zhikong scallops.The results showed that 6(including Platymonas subcordiformis,Chlorella sp.,Dunaliella viridis,and Tetraselmis tetrathele in Chlorophyta and Nitzschia closterium minutissima, and Skeletonema costatum in bacillariophyta)of 17 microalgae,which account for 35.3% of the tested algae,could carry AVNV,the AVNV detections in microalgae were positive during 96 to 144 h.The 6 AVNVmicroalgae complex were fed to zhikong scallops,the tested scallops show a typical acute viral necrobiosis symptom,and the accumulated mortalities of scallops fed with the AVNVmicroalgae complex were significant(P<0.05)or highly significant(P<0.01)compared with that of the control fed with mixture with 6 species microalgae during the nineday experiment,which indicated that the AVNVmicroalgae complex have an impressing ability to infect the scallops.Based on these laboratory challenges studies,the microalgae can serve as a vector in the horizontal pathway of transmission of AVNV via feeding or filtering process of scallops.

Abstract:Peroxisome proliferatoractivated receptors(PPARs)are a family of ligandactivated nuclear transcription factors that play pivotal roles in lipid and energy homeostasis.A cDNA of 1 688 bp encoding PPARγ was isolated from liver total RNA of Japanese Seaperch(Lateolabrax japonicus)using RT-PCR by degenerate primers based on sequence of other animals published on GenBank.The obtained 1 688 bp Seaperch PPARγ included 1 569 bp open reading frame encoding a protein of 522 amino acid residues with a theoretical pI of 6.06 and molecular weight of 59.02 ku.The blast analysis indicated that the deduced amino acid sequence of Seaperch PPARγ shared the highest identity of 93.1% with Dicentrarchus labrax,92.3% with Sparus aurata and 61.8% with Homo sapiens. RT-PCR analysis showed that the Seaperch PPARγ was ubiquitously expressed in 9 tissues tested,with the highest expression in liver,gill and lipid tissues,followed by spleen,brain,intestine and kidney,the lowest in heart and muscle.The cDNA sequence of PPARγ open reading frame was cloned into a prokaryotic expression vector pET-28a(+).The recombinant plasmid pET-28a-PPARγ1569 was transfected into Escherichia coli.BL21(DE3)pLysS and the PPARγ expression was induced at 30 ℃ by addition of 1 mmol/L isopropylβdthiogalactopyranoside.After 4 h induction with IPTG,the expressed recombinant protein with an apparent molecular mass of 66 ku was found by SDS-PAGE and confirmed by Western-blotting using an antibody specific to 6His tag.The expressed PPARγ protein was insoluble and present in the inclusion bodies.These inclusion bodies were solubilized by 6 mol/L guanidine hydrochloride and purified on a Ni²⁺ affinity column(Ni²⁺ Hisbinding column).After purification,the recombinant PPARγ was used to immunize mice and the specific polyclonal antibody was obtained.Indirect ELISA(enzyme linked immunosorbent assay)was established to test the titer of the polyclonal antibody,the result was positive and the titer reached 16 000.Our research serves as a basis for further research into fish PPARγ’s biological characterization and function.

Abstract:During the summers of years 2005,2006 and 2007,68 species of commercial aquatic products were collected from Mindong ecological monitoring area,Fujian east coast,P.R of China,and the residues of hexachlorobenzene(BHCs)and dichloro-diphenyl-trichloroethane(DDTs)were quantified by gas chromatography.The residues levels,distribution patterns and compositions of BHCs and DDTs,as well as the pollution status and the risk to human health were also evaluated and discussed.The results showed that,the residues of BHCs in shellfish,shrimps,crabs and fishes ranged from undetected to 1.53 μg/kg,undetected to 0.830 μg/kg,undetected to 1.21 μg/kg,undetected to 4.02 μg/kg,in wet weight respectively; and the residues of DDTs ranged from 0.184 to 66.9 μg/kg,undetected to 2.87 μg/kg,8.04 to 126 μg/kg,0.891 to 310 μg/kg,in wet weight respectively.BHCs pollution index was below 0.5,which indicated that commercial aquatic products along Mindong ecological monitoring area had not been polluted by BHCs.71.2% of tested samples with the DDTs pollution index range from 0.581 to 31.0,which indicated they had been more or less polluted by DDTs.BHCs levels in organisms from Mindong ecological monitoring area were lower compared with those reported in other sea waters at home and abroad.DDTs residues were in the middle levels compared with those reported in domestic adjacent waters and were relatively higher compared with those reported in AsiaPacific region waters.The average ratios of p,p′-DDT/DDTs in shellfishes and fishes were 43.8% and 49.1% respectively.High percentage of p,p′-DDT content may suggest that some contaminants such as DDTs had input into the Mindong ecological monitoring area in recent years.The residues levels of BHCs and DDTs were below the Maximum Residual Limits published by the European Union,USA and Japan; and met the sea food safety index set by Chinese government.The risk of organochlorine pesticides to human health was assessed according to RfD (reference dose),and cancer slope factor suggested by EPA(US EPA,2000).The analyzing of ERI(exposure risk index)and CRI(carcinogenic risk index)indicated that the exposure risk and carcinogenic potential arising from the exposure to BHCs and DDTs due to the consumption of aquatic product in Mindong ecological monitoring zone were within acceptable ranges.

Abstract:A male differentially expressed cDNA library subtracted from the female gametophytes of Laminaria japonica was constructed by use of suppression subtractive hybridization(SSH).A clone b9 was found to be a new differentially expressed gene using Southern dot-blotting.With the designed genespecific primers on basis of Clone b9 sequence,a full length of cDNA was cloned by use of rapid amplification of cDNA ends(RACE).This gene was composed of 831 bp in sequence including a 182 bp 5′-untranslated region(UTR),a 199 bp 3′-UTR with a poly(A)tail,and a 450 bp open reading frame(ORF).There was no difference in sequence of this gene no matter where it was cloned from the females or the males.Protein homology searching result showed that it was homologous to Nostoc punctiforme SpoIID/LytB domaincontaining protein(sporulation resulting in the formation of spores)with 30% similarity.This gene,therefore,was named sporulationrelated protein gene(srp)(GenBank accession No.EF490313).The srp gene was ligated into pET28a expression vector and was consequentially transformed into Escherichia coli BL21 competent cells.A recombinant protein was successfully expressed in prokaryotic cells with molecular weight of about 19.3 ku,and its expression was positively related to the content of inducer ITPG.Mass spectrometry analysis verified that the sequence of expressed recombinant protein was the same as the putative one on the basis of srp gene ORF sequence.The recombinant protein was purified from the transformed E.coli and its polyclonal antibody was obtained by inoculating immunologically rabbits.The SRP protein was proved to be present in the crude extracts from both the female and male gametophytes of L.japonica by using Western blot with the preparative antibody.The results lay a foundation for the further study on the isolation and characterization of SRP protein from gametophytes and on the investigation of function of SRP protein during the growth and development of L.japonica gametophytes.

Abstract:Under the conditions of synthetic water,the exposure method of mixed system and sequential system were adopted,the interaction of the two metals(Zn and Cd)was studied in different organs and tissues(gill,hepatopancreas,muscle)of the Eriocheir sinensis,in the process of absorbing accumulating heavy metal.The results show that the interaction of Zn and Cd was influenced by the exposure concentration,tissues and organs,the exposure time.In the mixed exposure system,Zn and Cd in the hepatopancreas showed a clear synergistic effect.In the gills,low concentration exposure showed synergistic,high concentration exposure showed antagonism.In the muscle,no significant change in the law.In the sequential exposure system,compared with the mixedexposure system,different organs and tissue content of Zn and Cd reduced significantly(P<0.05).The addition of Cd,will reduce the Zn concentration in the gill and hepatopancreas of Eriocheir sinensis in the Zn pre-exposure system,Zn content and Cd concentration have the antiexposurerelated,and Zn in the muscle did not change significantly.The addition of Zn,will increase the concentration of Cd in the Cd pre-exposure system of Eriocheir sinensis in gills,hepatopancreas and muscle,and hepatopancreas and muscle of Cd and Zn content were positively related to exposure concentration.

Abstract:Female southern flounder(Paralichthys lethostigma)grow larger than males.Therefore,allfemale production will maximize profit potential for the culture of this species.It may be effective to develop protocols to produce allfemale southern flounder through induction of meiotic gynogenesis with the cryopreserved heterologous sperm of Lateolabrax japonicas.To test methods for inducing diploid gynogenesis in southern flounder using heterogenous sperm,the UV was used to inactivate sperm and pressure shock was used to prevent extrusion of the second polar body.The results of experiments showed that gynogenetic diploid can be induced by inactivated heterogenous sperm because that hybrid would die before hatching.Diploid gynogenesis was induced by activating egg development with UV irradiated sperm(80 mJ/cm²) 4-5 min after fertilization(18 ℃),and then 65 MPa pressure treatment for 6 min.Flow cytometry and microsatellite DNA analysis were used to demonstrate that the gynogenetic fry are diploidy.These results indicate that the use of UV irradiated sperm from Lateolabrax japonicas for activation of flounder eggs and pressure shock for polar body retention is an effective method to produce gynogenetic diploid in southern flounder.

Abstract:Because the current common use crab pots(pot diameter 60 cm,height 25 cm,mesh size of clothing net 2a=32 mm)are causing the serious damages on the juvenile crab resources of Portunus trituberculatu in the East China Sea,a selective crab pot with escape gap opened on the framework for juvenile crab was designed.The productive tests in 32°30′-33°00′ N,124°00′-124°30′ E were carried out during Nov.2009.The results showed that the proper height of the escape gap is almost the same as the largest shell height of P.trituberculatu.If the minimum criterion of catchable body weight was 125 g,the height of selective escape gap was 33 mm which can be estimated from the relationship between shell height and body weight; The selection curve of the escape gap can be described by piecewise function without 50% selective shell height,which is different from “Logistic selection curve” that is usually used to describe the mesh selection curve of trawls,shrimp trawl,stow net and eel pot with 50% selective length.The selective rate in number can be denoted by the average selection rate of shell height groups,by ChiSquare(χ²)test,while its values of productive tests were smaller than 20%,it presents higher release rate; however,it shows almost no effects caused by the size of gap for escaping,on the survival of juvenile crab were observed.At the same time,we suggest the minimum size of catchable criterion could be referenced for the formulation of the fishery regulation.

Abstract:In the present study,the growth performance and the effects of overwintering weight loss on the growth of Heilongjiang carp(Cyprinus cario haematopterus)(YL),selective line of German mirror carp(Cyprinus carpio L.mirror)(JL)and coldresistance line of Hebao red carp(Cyprinus carpio var.wuyuanensis)(HL)are evaluated by using passive integrated transponders(PIT)technique.The offspring populations of YL,JL and HL were generated at the same hatching time and under the same rearing conditions,PIT tags were implanted in the muscle of all experimental individuals on 135 d(day).Afterwards,the related growth indexes were measured on 135 d(before overwintering),325 d(after overwintering),385 d and 445 d,respectively.The results demonstrated that the special growth rate for body weight of JL was significantly greater than that of YL and HL only during 1-135 d(P<0.05),while YL had faster special growth rate for body length than that of JL and HL not only during 1-135,but 325-385 d(P<0.05).The coefficients of variability for body weight in each breed(line)exceeded 20% in each detected period indicating there was a large variation of body weight between individuals within the same breed(line).For each population examined,though male fishes had greater gonad weight and mature coefficient of gonad than female fishes on 445 d(P<0.05),significant difference of growth rate between male and female was not observed during the whole experiment.In addition,there was significant positive correlation between overwintering weight loss rate and body weight before overwintering in three carp breeds(P<0.01).Interestingly,overwintering weight loss rate between individuals with the same body weight scale in each carp breeds(lines)varied greatly,and these individuals could be subdivided into 2 populations with low weight loss(LWL)and high weight loss(HWL).The body weight of the LWL population was significantly lower than that of the HWL population on 135 d(P<0.05),while the LWL population had higher body weight on 325 d,385 d and 445 d than the HWL population(P<0.05).For body length performance,the LWL population was higher than that of the HWL population in each detected period(P<0.05).The overwintering weight loss rate had no correlation with the special growth rate for body weight during 325-385 d and 385-445 d,but had significantly negative correlation with the body weight on 385 d and 445 d(P<0.01).

Abstract:Sensory attributes,total number of bacteria,physical and chemical parameters(proximate composition,texture analysis,color measurements,pH,TBA,TMAN,TVB-N,K-value,Ca²⁺-ATPase activity,SDS-PAGE)changes of yellow grouper(Epinephelus awoara)stored under vacuum packaging at 0 ℃were investigated.The results showed that yellow grouper was a fish with low level of fat but high level of protein.During the storage,sensory attributes(odor and taste)exhibited significant variations and correlations in storage time(r=0.94 and 0.98,respectively).Taste score increased faster than the odor score,however,neither of them reached the reject limit of 3 scores.There were significant linear increases in total viable counts(TVC)in the storage(r=0.97).TVC on the 12th-day was lower than 4 Log CFU/g,indicating the fillets kept at first grade of freshness,and was 4.34 Log CFU/g at the end of 15 days storage,kept at second grade of freshness.With regards to the texture profile,hardness(r=-0.89),gumminess(r=-0.73),chewiness(r=-0.87)showed a significant and negative correlation with storage time.L^* and the chroma values decreased,and b^* values increased,reflecting the colour changes experienced by the fillets over time.No significant differences were found in pH and TBA concentrations during the storage and they displayed a weak correlation with time,so they may not be the suitable indicators for reflecting the quality changes of yellow grouper fillets during the storage.The amount of TVB-N and TMA-N significantly increased with time,at the final of storage,TVB-N and TMA-N reached 12.94 mg N/100 g and 0.75 mg N/100 g respectively,and both of them were lower than limit.The proteolytic degradation of muscle protein was observed by SDSPAGE,the results showed that MHC and Actin were hydrolyzed continuously throughout storage.Ca²⁺-ATPase activity declined fast from the initial value of 0.25 μg Pi/(min·mg)to the final value of 0.07 μg Pi/(min·mg).K value increased fast with time(r=0.98)and reached 54.91% at the end of storage,keeping the middle level of freshness.The results suggested that total viable counts(TVC)increased slowly under vacuum packaging at 0 ℃,and it kept good sensory characters,inhibited the changes of the paraments(TVB-N value,etc.)and hydrolysis of protein.The sensory attributes,microbiological counts,texture(hardness,cohesiveness and chewiness),colour(L^*、b^*,and Cab),TVB-N,TMA-N,Ca²⁺-APTase activity and K value exhibited strong correlations with storage time and were sensitive.Therefore,they may be considered as good indicators for evaluating yellow grouper spoilage during the storage under vacuum packaging at 0 ℃ for 15 days,but the consideration of shelflife should be combined with all those indicators.

Abstract:In order to improve the phenotypic character of Manila clam Ruditapes philippinarum,three way crosses between Two-band Red(R:fast growth)and White Zebra strains(WZ:obvious heterosis)were conducted in August 2009.The generation F2 of White Zebra strain was from two way crosses between Pearl White and Zebra strains.The experiments consisted of two selffertilized groups(RR,WZWZ)and two hybrid groups(RWZ,WZR).Then the growth,survival,heterosis and shell color genetic mechanism were investigated in the study.The results showed that the singleparental heterosis was asymmetrical between two reciprocal crosses,and the growth and survival were clearly improved in RWZ group,whereas only survival heterosis was observed in another group.Considering growth,the value of midparental heterosis was -0.68,and that of singleparental heterosis was +1.70 for RWZ,and -2.92 for WZR,respectively.It was mainly affected by the interaction between egg origin and mating strategy,next is maternal effect during planktonic stage.The value of midparental heterosis was only +0.90,and that of singleparental heterosis was +9.71 for RWZ,and -6.57 for WZR during juvenile stage.Considering survival,the value of midparental heterosis was +3.60,and that of singleparental heterosis was +4.47 for RWZ,and +3.05 for WZR,respectively.It was mainly affected by the mating strategy,next that is maternal effect during planktonic stage.The value of midparental heterosis was +9.00,and that of singleparental heterosis was +13.09 for RWZ,and +7.30 for WZR during juvenile stage.The shell color of generation for R×R,R×WZ,WZ×R,WZ×WZ were two band red,two band red with white zebra,two band red with white zebra and white zebra,respectively.The generation of white zebra was still white zebra on the outer shell color,that is,no shell color separated for two way hybrids.These results indicated that coloring was linked to sex and was not of sex-linked inheritance.

Abstract:The quality and texture changes of Lateolabrax japonicus meat during partially frozen storage were studied.Tissue structures,texture profile analysis and changes of rheological properties(elastic modulus E₀, stressrelaxation time τ₁, viscosity η₁, rupture strength),combined with the total number of bacteria,K value,TVB-N,pH value and sensory scores were determined.The results suggested that the total number of bacteria,K value and TVB-N increased with the extension of storage time,while pH value decreased and then increased.The increasing speed increased with temperature.As the storage time extended,the pores of the myofibril increased,the tissue structure deteriorated,elastic modulus E₀ increased, and rupture strength,hardness,springiness,cohesiveness and chewiness decreased,while viscosity η₁ and stressrelaxation time τ₁ have no significant changes.Compared with that of the refrigerated samples,the shelflife of partially frozen storage samples could be extended for 20 days.It showed partial freezing could effectively inhibit the activity of enzymes in the meat of Lateolabrax japonicus and the effect of micro-organisms, so that it could alleviate the decomposition of protein.As a result,partial freezing storage is an effective method to extend the storage time of Lateolabrax japonicus.

Abstract:Methyl farnesoate(MF)is an important hormone controlling crustacean growth.Our previous study has demonstrated that the treatment of juvenile hormone antagonist KK-42 can accelerate growth of Litopenaeus vannamei.In order to research the possible molecular mechanism of KK-42 growthpromoting effect onL. vannamei, a part of mRNA sequence of 3-hydroxy-3-methylglutaryl-coenzyme A reductase(HMGR),a key enzyme of MF precursor production,was cloned and the spatial and temporal expressions of HMGR and the effect of KK-42 on the expressions were assayed.The shrimps(L. vannamei),3.5-5.0 cm long,were soaked for 1 min in KK-42 solution at a concentration of 1.95×10^-4 mol/L or in the solution without KK-42,and then cultured in normal way.The HMGR mRNA levels derived from tissues were assayed using real-time PCR and hemolymph MF titer was determined by high-performance liquid chromatography(HLPC).Results showed that the highest level of HMGR transcript occurred in mandibular organ(MO),then in eyestalk and the lowest in muscle and hepatopancreas.The expression pattern of HMGR derived from eyestalk and MO tissues varied in control group during the experiment,of which no statistical difference in the mRNA level was observed in the eyestalk,but the mRNA content rose significantly on day 1 and day 7 compared to day 0 in the MO; the MF titer gradually increased during the experiment and was observed.Administration of KK-42 resulted in important depression on HMGR expression,and the change trend of the downregulated mRNA levels,however,differed in the two tissues mentioned.For eyestalk,the HMGR mRNA levels at all time points had no statistical difference,but those fluctuated and even reduced by 80.2%(P＜0.01)and 90.7%(P＜0.01)on day 1 and day 7 after KK-42 treatment,respectively,in MO.Meanwhile,the amount of hemolymph MF fell in KK-42treated shrimps compared to that in control ones during the experiment.Our present study demonstrates that treatment of KK-42 significantly inhibits HMGR expression in different tissues especially in MO,and decreases the hemolymph MF titer,which is likely one of mechanisms of KK-42 growthpromoting effect on L. vannamei.