Abstract:The effect of replacing fish meal with raw and various processed soybeans meal on growth and protein metabolism of common carp Cyprinus carpio was evaluated in an 8week trial. The common carp fingerlings［initial body weight(5.89±0.36) g］ were fed five isonitrogenous and isocaloric feeds(30% digestible protein and 15 MJ/kg digestible energy) containing SBM replacing 50% of the fish meal protein,such as raw soybean(RSB), processed soybean by chemical inactivator, processed soybean by heating, processed soybean by heat alcohol, respectively. Results showed that weight gain of control were significantly different（P>0.05），but those fed RSB were significantly lower than control（P<0.05）,those fed processed soybeans by chemical inactivator and by heating and by heat alcohol had no significant difference, but all significantly higher than control. Protease specific activity of control in the intestine and hepatopancreas was significantly higher than those fed RSB and processed soybeans by heat alcohol,but both had no significant difference with those fed processed soybeans by chemical inactivator and by heating（P>0.05）. RNA of 100% fish meal and 50% processed soybean by heating in white muscle were no significant difference(P>0.05），but both were significantly higher than those fed RSB and processed soybeans by heat alcohol and by chemical inactivator and by heating, RNA/DNA of 100% fish meal and 50% processed soybean by heating and by chemical inactivator in white muscle had no significant difference(P>0.05），but all were higher than those fed raw soybean(RSB) and processed soybean by heat alcohol（P<0.05）. RNA in white muscle and serum IGF-I had a positive correlation with growth(P<0.05).The degree of negative effect of soybean antinutritional factors on fish is antitrypsin inhibitor>agglutinin>soybean antigen protein under the experimental conditions, and proper control could reduce the negative impact of soybean antinutritional factors on fish.

Abstract:Oriental river prawn (Macrobrachium nipponense) is one of the most important freshwater prawns for aquaculture in China. However, M. nipponense farming recently declined due to genetic retrogression. Its genetic diversity of different populations in the Yangtze River with microsatellite markers was investgated in order to give support to conservation and utilization of wild resources of M. nipponense. Twenty polymorphic microsatellite markers were applied to investigate the genetic diversity of 6 M. nipponense populations in the Yangtze River. The sampling sites included Chongqing, Wanzhou, Yichang, Wuhan, Jiujiang and Jiangyin. The average number of alleles (A) and effective numbers of alleles (N_e) in 6 populations were 5.25 and 3.462 2 respectively. The mean PIC value of 20 microsatellite loci was 0.589 4. Expected heterozygosity (H_e) of 6 populations was as follows: Jiangyin (0.630 8), Jiujiang (0.609 6), Yichang (0.594 5), Wuhan (0.593 4), Wanzhou (0.584 4) and Chongqing (0.582 1), and their mean value was 0.629 6. The analysis of molecular variance (AMOVA) indicated that almost majority of the variance in the M. nipponense was within populations (93.08%) ，and 6.92％was among populations. The F_ST values between populations were 0.025 3-0.083 8(P<0.05), which showed the genetic divergence between populations in the Yangtze River was intermediate but lower than that in the lakes. It was probably because running water promoted the exchanges between populations. HardyWeinberg equilibrium analysis indicated that deficiency of heterozygote existed in all of 6 populations, which was probably because of rare allele deficiency or null alleles. The genetic distances among populations ranged from 0.062 0 to 0.180 9. The UPGMA tree showed that Jiangyin stock formed an independent clade and resident 5 populations formed another one in which Jiujiang and Wuhan populations clustered at first.

Abstract:Vitamin B₆ or pyridoxine in the form of pyridoxal phosphate participates as a prosthetic group of enzymes in a large number of metabolic reactions, particularly those associated with the metabolism of proteins and amino acids. With the success of artificial propagation and larval production, the culture of cobia becomes widely distributed in southern coastal provinces of China(especially in Guangdong and Hainan Provinces) as well as Southeast Asia. However, currently the growth of cobia heavily depends on trash fish and the development of formulated feeds for cobia is still in its infancy. The objective of this study is to detect the optimal requirement of pyridoxine in diet of juvenile cobia Rachycentron canadum.Basal diet was formulated using vitaminfree casein, gelatin and fish protein concentrate as the protein source. The graded levels of PN(0,2,4,8,16 and 32 mg/kg diet) were added to the basal diets to formulate six experimental diets containing 0.22,1.89,3.87,7.54,14.75 and 29.88 mg PN/kg diet, analyzed by HPLC, respectively. Each diet was fed to three replicate groups of cobia in 300 L tanks for 9 weeks, and each tank was stocked with 25 fish ［initial weight （3.23±0.06） g］. The water salinity was from 30 to 34, temperature fluctuated from 28 to 32 ℃ and dissolved oxygen was above 7 mg/L. The results showed that specific growth rate(SGR) have an increasing trend with the increase of dietary pyridoxine(from 0.22 to 3.87 mg/kg), but no significant differences were observed among diets containing 3.87 mg/kg PN or above. The contents of PN and AST in liver of fish fed diets with 3.87 mg/kg were significantly higher than the treatments with the contents of PN lower than 3.87 mg/kg, however, there were no significant differences among diets containing 3.87-29.88 mg/kg PN. The contents of PLP and the activities of ALT of the diet containing 7.54 mg/kg PN were significantly higher than the diets containing PN<7.54 mg/kg, however, no significant differences were discovered among diets containing PN>7.54 mg/kg. The dietary pyridoxine requirement was estimated to be 3.09-3.26 mg/kg by the brokenline model based on the SGR, and the activities of ALT in fish liver.

Abstract:For analyzing phenotypic correlation level of growth traits at different developmental stages, three different strains of Artemia sinica were collected from different provinces in China. Fifty larvae per strain were selected randomly and reared separately for 30 days. In this growth period, the total length (TL) of A. sinica was measured every 5 days. The body length (BL), body width (BDW) and body weight (BW) were also measured at the last two stages. Then phenotypic correlation coefficients of growth traits among the different stages were estimated at individual level. The results indicated that the smaller the correlation coefficients were, the longer the intervals between two stages were. For example, the correlation coefficients between 5 d and 25 d were only 0.073, 0.091 and 0.026 for SIN, YIM and ALXZ respectively. Moreover, the correlation coefficients among the stages before and after 15 d were even negative. It was implied that the early stage selection method was not applied to improve growth traits in A. sinica, especially when selecting at the stages before 15 d. Although significant positive correlation were found among four growth traits at 25 d and 30 d stage， the correlation coefficients were smaller than expected. It was implied that BL and BDW could not substitute for BW as breeding object traits when breeding fastgrowing new strain with large body shape. The multitraits aggregated selection method based on selection index theory will be needed for the above breeding object.

Abstract:Statoliths are paired calcified structures within the statocyst providing a sense of balance, and they are also an acceleration receptor showing much information about biology and ecology over the life span. With the study and application gradually elevation and improvement for otolith microchemistry of fish, corresponding study in the statolith of cephalopod become popular. Recently, microchemistry study is one of hot topics in fishery animal, and more and more scientists are interested in it as so much biology and ecology information was showed. For the purpose of providing some reference to the researchers, studies of microchemical structure of cephalopod statoliths were reviewed. Presently, the main contents for microchemistry study in cephalopod statolith are composed of inorganic and organic molecules, minor and trace elements, isotope as well as microchemical markers. Minor and trace elements were the important part among the application, which played an important role in discriminating different populations, analyzing life history and reconstructing inhabited environment condition. Some good results have been shown regarding relationship between the elements and environment condition especially water temperature, some of which were considered as a thermometer for reconstructing environment temperature. However, studies refer to population discriminating, life history analyzing and influence by salinity and food for the elements were not enough, moreover, most of study concentrated on strontium to calcium. Therefore, we proposed that the elements value study should be performed at daily level according to different temporal and spatial serial in the further research.

Abstract:In order to develop a simple and efficient protocol for isolating total RNA from thalli of Porphyra haitanensis, three methods(CTAB method, SDS method, Guanidine thiocyante method) which were commonly used to isolate and purify total RNA were improved based on the methods of wiping off polysaccharides and polyphenol， and absorbency method, electrophoresis method and RT-PCR method were employed to determine the quality and quantity of RNA. RNA isolated by spin column kit method and RNAiso method was also compared with the RNA by the three methods. The results show the total RNA isolated by SDS method, guanidine thiocyante method and RNAiso method was of poor purity, retained some protein and polysaccharide and some RNA have dissolved into single nucleotide acid. But the total RNA which isolated by CTAB method and spin column kit method was of good quality and high purity, the substance which can restrain the active of reverse transcription enzyme also was cleared. These results suggest that CTAB method and spin column kit method are fit for the isolation of total RNA from the thalli of P.haitanensis, but each of the two methods has its advantages and disadvantages, we should choose the appropriate method based on the situation.

Abstract:Half-smooth tongue sole (Cynoglossus semilaevis) is an important cultured marine fish and shows large sexual dimorphism in growth. In general, the females grow about four to five times faster than males. However, the percentage of males in cultured group is higher than that of females. Is the sex ratio deviation from expected value(1∶1) associated with natural sex reversal？ In the present study, the natural sex reversal phenomenon in halfsmooth tongue sole was studied by means of female specific marker sex identification technique. We determined the phenotypic sex of 71 four-year-old halfsmooth tongue sole by means of abdominal compression during reproduction season. The individuals not producing sperm or eggs were injected with (0.4-2.0) μg/kg LRHA₃ and fed in concrete tanks until sexual maturation. In total, there were 39 phenotypic males and 32 females, and the mean body weight of phenotypic males was (0.339?0.078) kg and (1.471?0.214) kg of females. However, the body weight of one phenotypic male was 0.585kg and significantly higher than other males. The female-specific marker analysis also showed that the phenotypic male tongue sole produced female-specific band, but not other 38 phenotypic males; 32 phenotypic females all produced female-specific fragment of about 205 bp. As a result, the phenotypic male half-smooth tongue sole producing female-specific fragment could be natural sex reversal male(neomale). Large-scale genetically sexual identification of phenotypic males in Laizhou Mingbo Co. Ltd showed the rate of natural sex reversal was 1.66%. It also proved that phenomenon of natural sex reversal in tongue sole was universal. Histological analysis of the sex-reversal male gonads showed that they contained functional testicular tissue with sprmatocytes. However, the amounts of spermatocytes in sex reversal individuals were fewer than that in control males. The phenomenon of natural sex reversal of female half-smooth tongue sole is helpful to explain the high male percentage in cultivating group and provides a new technique to produce all-female half-smooth tongue soles.

Abstract:By analyzing 297 stomach contents of Sebastisous marmoratus in seaweed bed around Gouqi Island in April，May, June 2008 and August 2007, this paper studied the feeding habits of this species and its diet composition that varied with seaweed growth. Results showed that feeding intensity was low throughout the study period and percentage of empty stomachs and mean stomach fullness index varied significantly(P<0.05). Percentage of empty stomach varied insignificantly among the size classes(P>0.05). The mean stomach fullness varied insignificantly among specimens less than 80.0mm TL(P>0.05). S.marmoratus was benthivorous and the diet of it consisted of at least 29 different prey species belonging to 12 major groups(Amphipoda, Shrimps, Crabs, Echinodermata, Polychaeta, etc.). Amphipoda were the most important prey and accounted for 97.03% by %IRI of all the prey. The composition of the prey varied with different growth periods of seaweed bed and S. marmoratus size classes. Shrimps and crabs were more important during booming period and flourish period, whereas amphipods were more important during lasting peroid and decay period. Amphipoda were more important in the diet of specimens less than 80.0 mm TL, shrimps and crabs were more important in the diet of specimens 80.0-99.9 mm TL, whereas fish and amphipods occurred more in the diet of specimens less than 100.0 mm TL.

Abstract:The paper discusses the spatial variation of the small yellow croaker (Larimichthys polyactis) fishing ground annual changes in production and the dominance of fisheries according to the capture production of fishing in the Bohai Sea, Yellow Sea and East China Sea from 1971 to 1982. We also compared the locations of historical fishing grounds with the present locations and time, and we explored the spatial variation and the changes in fisheries. The results shows that there are three types of small yellow croaker fishing grounds, that is the spring spawning grounds which were mainly located in coastal waters, summer feeding grounds which were concentrated on the south of Yellow Sea and the north of East China Sea, and the wintering grounds which were concentrated on the central and southern offshore of Yellow Sea and northern nearshore of the East China Sea. The capture production of small yellow croaker in Bohai Sea had declined significantly since 1974 and the capture production in East China Sea was dominant since 1979. In addition, two kinds of distribution patterns of small yellow croaker were found. One is wintersummer (Dec, Jan.-Feb. & Jul.-Sept.) pattern, composed of highquality small yellow croaker fishing grounds for the stable locations located in the central and southern offshore of Yellow Sea and northern offshore of the East China Sea in winter and in the southern nearshore of Yellow Sea and the East China Sea in summer, intensive fish and concentrated production. The other is springautumn (Mar.-Jun. & Oct.-Nov.) pattern, which was characterized by the low capture production for the small yellow croaker in the migratory period and it was not the predominant target species for capture. The spatial distribution pattern fishing grounds for small yellow croaker in 1971-1982 resemble the current, but it has important reference value to research on small yellow croaker in the characteristics of fishing grounds, fishing season and the contribution of fish distribution pattern mode.

Abstract:Anguilla japonica, is one of the most important commercial catadromous fish species in Asia. Yangtze River estuary serves as the major production regions of larval eels and the only fishery waters of adult eels in China. In this study, we analyzed the age and growth characters for 153 migrating silver eels collected at Jingjiang reach of Jiangsu Province (31°30′N，120°42′E) from Sept. to Nov. 2008. The results showed that the age of the females in Yangtze River estuary ranged from 3-7 years with a mean of 5.52 years while the age of males ranged from 3-5 years with a mean of 4.38 years. The age structure of female eels is higher and more than male eels. Max. annual gain in length of both female and male A. japonica appeared in the 4th year. The growth parameters of females such as the age of inflexion point, the growth inflexion point of body length, the growth inflexion point of body weight, the average asymptotic body length and the average asymptotic body weight were t_i=5.20, lr=683.05 mm, Wr=546.37 g, L_∞=1 011.03 mm and W_∞=1 830.16 g, respectively, which were significantly larger than those of males, t_i=4.91, lr=517.15 mm, Wr=216.15 g, L_∞=750.30 mm and W_∞=715.90 g. The results indicated that the average age of migrating A. japonica in the Yangtze River Estuary was smaller than those of other regions in China and Japan. However, the average asymptotic body length of migrating A. japonica in the Yangtze River Estuary was significantly larger than those of other regions.

Abstract:Matings and crosses within and among two different geographic stocks from Shandong and Jiangsu populations in Meretrix meretrix were produced in order to breed new strains for farming. Two populations, designated S♀×S♂ and J♀×J♂, were from matings of wild populations of Shangdong and Jiangsu. Two populations, that was S♀×J♂ and J♀×S♂, were from crosses between Shangdong and Jiangsu respectively. The traits of fertilizing rate, hatching rate, growth of D-larvae and growth of juveniles (1-12 months age) were analyzed by ANOVA. The results showed that the fertilizing rate and hatching rate of matings and crosses were not significantly different at the end of second month. There were great changes of growth of juveniles in earlyterm (3-12 months). Growth of S♀×J♂, S♀×S♂ and J♀×S♂ had no significant difference from each other, but all had significant difference with J♀×J♂ at the earlyterm (3-12 months). The results indicated that there was different extent heterosis (6%-68%) for growth in F1 crosses. The uptrend among traits was wet weight being greater than other three traits of shell length, shell width and shell height respectively. There were obviously higher growth rate and lower variation coefficicent in S♀×J♂＞, which indicated the Shandong population would be a good parental stock as maternal for genetic breeding. Water temperature could affect growth of Meretrix meretrix significantly, and the growth rate reached a peak in October and November, but reached a nadir after December. Four populations gained were considered as the basic populations to breed new strains. Increased variation parameters in first filial generation(F₁) of cross could be a very good potential for selection of new strains.

Abstract:Histological changes of the digestive system and its associated glands were studied in jade perch, Scortum barcoo from the first day(first day posthatch, dph) to 30 dph. Specimens for this study were hatched from artificially spawned broodstock and maintained in the indoor plastic tanks(26.6-29.7 ℃). The newly hatched larvae had one big yolk sac, and their digestive tract was only a columniform diverticulum, without communication with outside. Digestive tract communication with outside in 30hourold larva and their mouth shut up. 2dayold larvae’s gut started crumple and peristalsis. The intestinal had been divided into anterior intestine and posterior intestine by intestinal valve. 3dayold larvae could be fed, the epithelial of digestive tract begun differentiation, mucous cells appeared in esophageal, pancreas and liver appeared. The nutrition of fish began transferred to the stage of mixed nutrition. In this stage, the digestive tract was differentiated into five portions: buccalpharyngeal cavity, esophagus, stomach, anterior intestine and posterior intestine, liver and pancreas had also been formed; these organs already had initial structure and the capacity of digestion and absorption. Along with the development of larvae fish, digestive system tended to perfect. Gastric glands appeared in the stomach of 21dayold juvenile, marking the beginning of juvenile.

Abstract:In order to obtain more molecule markers linked to growthrelated traits of tilapia and evaluate their accuracy, 65 microsatellites loci were amplified in two Nile tilapia populations (Luye and Panyu), and the markertrait association was analyzed by GLM（general linear model）procedure of SPSS software. The correlation analysis results showed that 8 loci(UNH130, UNH183, UNH911, GM558, UNH211, UNH176, UNH914 and UNH974) had a significant impact on major growth traits (weight, body length and body height) of Luye population(P<0.05 or P<0.01). In Panyu tilapia population, UNH914 and UNH974 had a significant impact on major growth traits (P<0.05 or P<0.01), and UNH176 just had a significant impact on body weight (P<0.05). The favorable genotypes or allele linked to growth traits including weight, body length and body height were determined by multiple comparison analysis between the phenotypic value and different genotypes of microsatellites markers linked to major growth traits. In this study, the microsatellite loci with a significant effect on growth traits were found, and they were potential valuable genetic markers for markerassisted selection of tilapia.

Abstract:The histological structure of the digestive tract of Siganus canaliculatus was studied by using light and electronic microscopy. The esophagus mucosa was composed of stratified squamous epithelium with many mucous cells and there were lots of glands in the submucosa. The stomach mucosa formed with a singlelayered columnar epithelium. The gastric cardiacus and caecum contained many glands while the gastric pyloricus contained less. The gastric columnar cells included more mitochondrion, rough endoplasmic reticulum and Golgi apparatus, some of cells had many pinosomes. The intestine epithelium was also singlelayered columnar epithelium, including a great number of goblet cells. Dense microvilli were observed on the free surface of the epithelium, junctional complex was present on its lateral edge and, abundant cell organs were present in its cells. There were a lot of multivesicular bodieson at the top of the epithelium cell of the intestine. With changes from foregut to hindgut, the height of folds decreased and the number of folds was reduced gradually, in addition, the muscular coat became much thicker. Large numbers of lymphocytes were distributed in the hindgut, which closely arranged in ring. The histological character of the pyloric caeca was similar to the intestine’s, but the epithelium cell of the pyloric caeca had denser multivesicular than the intestine’s. The results showed that there was close correlation between the characteristics of histology structure in digestive tract and digestion and absorption of S. canaliculatus.

Abstract:Reciprocal hybrids of olive flounder ♀(Paralichthys olivaceus)×summer flounder ♂(P. dentatus), olive flounder ♀(P. olivaceus) × barfin flounder ♂(Verasper moseri), olive flounder ♀(P. olivaceus) × turbot ♂(Scophthalmus maximus) were performed by artificial fertilization from 2005 to 2008. And data of hybridization on eight flatfish species in previous reports were also collected including barfin flounder (V. moseri) × spotted halibut (V. variegatus), stone flounder (Kareius bicoloratus)× starry flounder (Platichthys stellatus), summer flounder (P. dentatus) × southern flounder (P. lethostigma) and olive flounder (P. olivaceus) × spotted halibut (V. variegatus). The hybrid compatibilities of interspecific crosses on these eight flatfish species were analyzed. According to Russell’s definition, hybrid fitness was scored 1 when the offspring of reciprocal crosses were both viable. The hybrid fitness was scored 0.5 whe one direction of reciprocal crosses was viable, and hybrid fitness was scored 0 when the offspring of reciprocal crosses were both inviable. Meanwhile, the ribosomal RNA 16S (16S rRNA) partial sequences and the mitochondrial cytochrome c oxidase subunit Ⅰ (COⅠ) partial sequences of the eight flatfishes were obtained and analyzed. Based on combined sequence data of mtDNA 16S rDNA and COⅠ, intrespecific pairwise distances were calculated and a phyogenetic tree was constructed. The relationship between hybrid fitness of the flatfishes and pairwise genetic distances was evaluated and linear correlation existed between the two（R²=0.81， P<0.01）. The hybrid compatibilities declined with the interspecific genetic distances. Our results suggested that negetive correlation exists between hybrid compatibility and genetic divergence in flatfishes. The hybrid compatibility between different species of flatfishes could be predicted by analysis of interspecific genetic distance. And these results would be good references for further hybrid breeding study in flatfish.

Abstract:Chlorella vulgaris was cultivated for five days under the stress of 60 μmol/L of Zn²⁺ (ZnCl₂). After harvest by centrifugation, the algal cells were washed with EDTA and water, and were homogenized by a supersonic cell disintegrator. After centrifugation, the supernatant, a crude proteincontaining extract, was separated and purified with a gel filtration column (Sephadex G-75, 3.5 i.d.×80 cm) and a desalting gel filtration column (Sephadex G-25, 1.5 i.d. × 30 cm). The obtained Znbinding proteins were characterized with several analytical methods. Results showed that the molecular weight of the proteins measured with tricineSDS-PAGE was about 8.2 ku, and the cysteine content of the proteins was 15.4%. In addition, the characteristic ultraviolet spectrum of the proteins was found to be similar to that of the standard MTs from rabbit liver. Therefore, the Znbinding proteins were referred as metallothioneinlike (Zn-MT-like) proteins. Based on the agar hole pervasion method, the activities of antibacterial and antifungal of Zn-MT-like proteins were tested. The results showed that Zn-MT-like proteins strongly exhibited the antimicrobial activities against grampositive bacteria (including Staphylococcus aureus and Bacillus subtilus), Penicillium chrysogenum and Aspergillus niger, but was insensitive to Escherichia coli and brewer’s yeast. The diameters of inhibition zone for 1 mg/mL of Zn-MT-like protein were 13.2, 17.4, 7.2 and 9.8 mm for S. aureus, B. subtilus, P. chysogenum and A. niger, respectively. However, no anti-microbial activity was found for the standard Zn-MTs from rabbit liver. The antimicrobial activities of Zn-MT-like proteins from C. vulgaris may be helpful for the further comprehensive development and utilization of the alga.

Abstract:Genetic linkage maps of yellow catfish (Pelteobagrus fulvidraco) were constructed using SSR, SRAP and TRAP markers and a pseudotestcross mapping strategy. A segregating population including 100 progenies was sampled within the first filial generation obtained by artificial fertilization between a male parent and a female parent from wild and breeding populations respectively. Totally, 13 SSR, 89 SRAP and 26 TRAP markers were used to construct a genetic map. Female map included 16 linkage groups, covering a total of 585.5 cM in length. Male map included 15 linkage groups, covering a total of 752.3 cM in length. Combined map included 5 linkage groups, covering a total of 231.3 cM in length. This map was used to scan the QTL related to growth traits of yellow catfish. One head length QTLs were identified in female map located in LG7, LOD value is 3.2 and accounted for 13 % of phenotypic variation. A body width and a body length QTLs were identified in male map both located in LG1, LOD value is 2.4 and 2.1 respectively, and accounted for 12% and 11% of phenotypic variation respectively. Three QTLs could be considered to apply in markerassisted selection for growthrelated traits breeding of yellow catfish.

Abstract:Effects of immobilized microorganisms on regulation of water quality and bioremediation of polluted sediment in Litopenaeus vannamei aquaculture ponds were studied by measuring algae community structure, various water quality parameters, total organic carbon(TOC) of sediment and heterotrophic bacteria. Immobilized microorganisms included microorganisms immobilized by zeolite(ZE-M) and biological active carbon(BE-M). The results showed that the algae were more diverse, with similar proportions of cryptophyta, bluegreen and green algae in the ponds with immobilized microorganisms, while bluegreen algae dominated in the control ponds. Concentration of ammonia nitrogen and COD increased linearly with culture time in the control ponds, but increased more slowly in the treatment ponds, which was probably due to the application of immobilized microorganisms of ZE-M and BE-M. Other indices of water quality did not show significant difference between treatment and control ponds. Effects of immobilized microorganisms on TOC content in the sediment and amount of heterotrophic bacteria were significant(P<0.05). TOC content in the sediment in both treatment and control ponds increased with culture time, but TOC content in the control ponds increased more rapidly. At the beginning of the experiment, the amount of heterotrophic bacteria was 3.367×10⁵-8.60×10⁵ CFU/g, and increased to 85×10⁵-393.7×10⁵ CFU/g by the end of the experiment. The amount of heterotrophic bacteria between treatment ponds and control ponds was significantly different(P<0.05) with the lowest amount in the ZE-M group(21.59% of the amount in the control ponds). Our study showed that immobilized microorganisms could significantly improve water quality, increase algae biodiversity and bioremediate polluted sediment in Litopenaeus vannamei aquaculture ponds.

Abstract:A feeding experiment was carried out to evaluate the growth performance, fat metabolism and blood indices of diets containing different additives by crucian carp, Carassius auratus gibelio ［mean initial weight of (7.46 ± 0.2)g］, for 67 days. 450 healthy fish were randomly divided into five groups in the experiment, group 1 was control group fed basic feed, whereas groups 2,3, 4 and 5 were fed the basic feed added with 0.05% lysophospholipids, 0.1% lysophospholipids, 0.1% betaine and 0.15% cholinechloride, respectively. At the end of the experiment, growth performance, fat metabolism and blood biochemical parameters were observed to estimate the function of these three additives. The results showed that weight growth ratio (WGR) of carps in groups 4(added with 0.1% betaine )and 5(added with 0.15%cholinechloride) tended to be higher than that of fish in group 1 (control) and this difference was significant (P<0.05), and a lower feed conversion ratio (FCR) was found in groups 3 (added with 0.1% lysophospholipids), 4 (added with 0.1% betaine) and 5(added with 0.15%cholinechloride) too (P<0.05). The apparent digestibility coefficients (ADC) of nutrients and crude protein content in body composition were significantly higher in experimental groups than those in control group (P<0.05). However, the liver fat, muscle fat content in experimental groups were lower than those in the control group, of which the test group of liver body ratio, liver fat content was significantly lower than that in the control group (P<0.05). The triglyceride levels in groups 4 (added with 0.1% betaine) and 5(added with 0.15%cholinechloride) were lower than those in control group while the triglyceride levels in groups 2(added with 0.05% lysophospholipids) and 3(added with 0.1% lysophospholipids) were higher than those in control group (P>0.05). Reduced plasma cholesterol levels were found in experimental groups while the increased free fatty acid contents were observed in experimental groups (P<0.05). The experimental groups significantly increased superoxide dismutase (SOD) of the volume (P<0.05), reduced malondialdehyde (MDA) and alkaline phosphatase (AKP) of the volume (P<0.05), while aspartate aminotransferase (GOT), alanine aminotransferase (GPT), glucose (Glu) have no significant effect (P>0.05). In conclusion, it could improve growth performance, reduce the fat content in liver and enhance antioxidation function obviously by adding 0.1% lysophospholipids, betaine and 0.21% cholinechloride in basic diet of crucian carp,Carassius auratus gibelio in our study.

Abstract:Estrogens are key players in sexual differentiation and development and their production is essential for normal sexual development in both females and males. Cytochrome P450 aromatase is the terminal enzyme in steroidogenic pathway that converts androgens into estrogens. In most of vertebrates, P450arom is the product of the CYP19 gene, which exists as a single copy per haploid genome. In contrast, there are two isoforms of aromatase in teleosts, which are encoded by two different genes, CYP19a and CYP19b, as well as have different distribution. This work describes the molecular cloning of the cDNA encoding the barfin flounder (Verasper moseri) gonad cytochrome P450 aromatase(CYP19a) by means of reverse transcriptase polymerase chain reaction(RT-PCR), degenerate primers PCR amplification and 5′ and 3′rapid amplification of cDNA ends(RACE) analyses. We cloned the complete cDNA sequence of CYP19a gene and the length is 2 167 bp, encoding a protein of 523 amino acids. Via Blastn, the CYP19a cDNA displayed high identity with Atlantic halibut (Hippoglossus hippoglossus), Japanese flounder (Paralichthys olivaceus) and southern flounder (Paralichthys lethostigma). Alignment analysis using barfin flounder CYP19a gene deduced animo acid sequence and animo acid sequences of other species showed that there were transmembrane helix region, I-helix region, Ozol’s peptide region, aromatasespecific conserved region and hemebinding region in the deduced animo acid sequence. Phylogenetic analysis suggested the occurrence of a gene duplication for cytochrome P450 aromatase in the teleost lineage after its divergence from the tetrapods. Furthermore, the higher identity between barfin flounder P450aromA and P450aromAs of other teleosts suggested that they have the same origin. A semiquantitative PCR was developed to measure mRNA expression levels of CYP19a gene of barfin flounder. Expression analysis in different tissues demonstrated that P450aromA transcripts were highly abundant in brain, ovary and testis, less abundant in intestine, liver and kidney, showing that not only gonads can produce steroids but also other tissues have steroidogenic capability. And we analyzed the relative mRNA expression level of CYP19a in testes at different stages of reproductive cycle, there were the highest level at stageⅡ and the lowest level at stageⅤ. These changes in expression profiles may imply differences in the functionality of the enzyme between different stages, suggesting an important role for P450aromA in barfin flounder testes development.