Abstract:To optimize the ethanol extraction conditions of floridoside and to investigate the effect of floridoside on the myofibrillar protein freezing denaturation of grass crap surimi during frozen storage. Ethanol concentration, extraction temperature, extraction duration and liquor to material ratio were optimized by response surface methods. The salt-solubility of myofibrillar protein, sulfhydryl content, and Ca²⁺-ATPase activity, etc in surimi after being frozen for 6 weeks were detected. Results showed that the optimal extracting condition for floridoside was 72.3% ethanol with liquor to material ratio of 14:1 (mL/g), the extracting tempreture was 60℃, and the extracting time should be 4 h. Under these optimal conditions, the highest extraction ratio was 3.48%. Salt-soluble protein, sulfhydryl group contents, Ca²⁺-ATPase activity were effectively enhanced, and the water loss was decreased by addition of floridoside in surimi. After 4 weeks frozen, salt-soluble protein and sulfhydryl group contents were enhanced by 30.62% and 32.80%; Ca²⁺-ATPase activity in myofibrillar proteins was reduced by 37.51% in 10% floridoside treated group, while the water loss ratio was 133.07% lower than that of the control group. This study indicates that floridoside can effectively prevent myofibrillar protein denaturation during frozen storage.

Abstract:In order to figure out the possible reasons of the different migratory distances between Coilia mystus and C. nasus, we investigated the relationships between migration distance of the two sibling species and lipid reserves and transfer in this paper. Study of C. mystus showed that individuals arriving at spawning ground in May were significantly greater in body length than those in June, July and August. In particular, those larger-sized females with higher somatic lipid content arrived at spawning ground and spawned earlier than others. The average hepatosomatic index of C. mystus was relatively higher than that of C. nasus during the same development period, and the gonadosomatic index of C. mystus at stages III and IV was about five times higher than that of C. nasus, indicating more energy centralized in ovary and easy-transferred organs of C. mystus during the spawning season. Although lipid content in muscle and liver of C. mystus was about one-third and half of that in C. nasus respectively during the same development period, C. mystus accumulated more lipid in ovary, a reproductive organ. Total trunk lipid in C. nasus decreased from 97.73% at phase II to 91.02% at phase IV, compared to rapid decrease from 91.02% at phase II to 34.69% at phase V in C. mystus. The amount of lipid in hepatopancreas was relatively stable in both species, whereas the lipid proportion in ovary of C. mystus was obviously higher than that of C. nasus. The finding that C. mystus allocated most of the body lipid for gonadal development and rapidly consumed trunk lipid may represent the common characteristic of short-distance migratory fish.

Abstract:The red giant sea cucumber (Parastichopus californicus) is native to the west coast of North America, and is under quota fishery in the United State of America and Canada. As a result of global over-fishing of sea cucumbers and increasing market demand, it is in urgent need to develop artificial breeding of P. californicus to promote the development of aquaculture. In order to develop artificial breeding of P. californicus, the embryonic and larval development of P. californicus was observed and recorded in the present study, and the size variations of fertilization eggs, embryos and larvae were measured under a microscope. The results showed that the gonad of P. californicus could be ripened by artificial diets, and the spawning of brood stock could be induced by desiccation method, in which the artificial fertilization rate exceeded 95%. The embryonic and larval development of P. californicus can be divided into the following stages:fertilization egg, cleavage, blastula, rotary blastula, gastrula, early auricularia, mid auricularia, late auricularia, doliolaria, pentactula, and juvenile. At the water temperature of 14℃, the salinity of 30 and pH of 8, the polar body occurred in 10 to 20 minutes after fertilization, and the eggs started cleavage in 1 hour, and went into rotating blastula stage in 1 day, and went into gastrula in 2 days, and went into early auricularia in 4 days. It took a total of 15 days for fertilization eggs to develop into doliolaria stage, and 18 days to develop into juvenile stage. The auricularia P. californicus reached a maximum body length of 1125.0 μm. This is the first study on embryonic and larval development of P. californicus, which may provide scientific basis for the hatchery rearing, and artificial breeding of red giant sea cucumber.

Abstract:The influences of different light qualities (green 510-550 nm, blue 455-475 nm, red 580-630 nm, white 400-760 nm) from light-emiting diode (LED) illuminations on the growth and physiological characteristics of wild free-living conchocelis of Pyropia haitanensis were studied. Results showed that blue light (BL) significantly promoted the growth rate of conchocelis in the cultures. The weight increments of conchocelis under BL were 1.10, 1.82, 2.17 times higher than those of other conchocelis cultured under white light (WL), green light (GL) and red light (RL), respectively. BL stimulated the synthesis of chlorophyll a and carotenoids. Compared to WL, GL and RL, the contents of chlorophyll a in BL were increased by 13.77%, 47.69%, 63.42%, respectively, and the contents of carotenoids in BL were increased by 8.87%, 87.07%, 97.73%, respectively. BL and WL were conducive to synthesize phycoerythrin rather than GL and RL. However, there were no significant differences of phycocyanin contents between the conchocelis in the cultures under different LED light qualities. Moreover, BL resulted in the highest activity of carbonic anhydrase, which enhanced by 11.36% than those of WL. Compared to WL, both BL and GL significantly stimulated the activity of ribulose bisphosphate carboxylase, which enhanced 28.17% and 61.21%, respectively. In the late growth stage, the conchocelis cultured under RL and GL were discolored and short of satellite chromatophore, even parts of them overflowed their cell inclusions and were hollowed. Whereas, conchocelis under BL and WL were normal, healthy and bright red. Therefore, we could add suitable component of blue-light, and decrease red-light and green-light in the asexual propagation of free-living conchocelis in P. haitanensis.

Abstract:The seasons of autumn and winter are the main fishing time of Trachurus murphyi. It has practical meaning to establish the forecasting model of fishing grounds for T. murphyi. In this paper, we established the habitat suitability index of T. murphyi during autumn and winter based on Chinese commercial fishing data of T. murphyi in Southeast Pacific during May to September from 2003 to 2009 and combined with oceanic environmental data including sea surface temperature (SST) and sea surface height (SSH). The fishing effort and CPUE are considered as the indicator of suitability index (SI), and the curves of SI were estimated by using the method of Data Envelopment Analysis. And the Arithmetic Mean Model (AMM), Geometric Mean Model (GMM) and the weighted AMM are used to establish the integrated habitat suitability index (HSI). The fishery data in 2010 and 2011 are used to compare and test the HSI model. The results indicated that the SI curve based on fishing effort is better than that based on CPUE, and the AMM is better than that the GMM. The weighted AMM is also more suitable than the general AMM, and the monthly suitable weight of SST during May to September is 0.4, 0.7, 0.5, 0.7 and 0.1, respectively. In 2010 and 2011, in the fishing areas with greater than 0.6 of HIS, the percentages of catch and fishing effort attained 75%-93% and 80%-90% respectively. It is concluded that the habitat suitability index during May to September based on fishing efforts by using external envelope method with monthly weights of SST could be used to predict the fishing ground of T. murphyi. In different months, SST and SSH have different effects on fishing ground of T. murphyi during autumn and winter.

Abstract:Triploid of Crassostrea hongkongensis was induced by blocking the second polar body release by cytochalasin B(CB) and 6-dimethylaminopurine (6-DMAP), and we compared the two methods in the aspects of triploid rate, cleavage rate, velar larvae gain, cost and so on. The effects of the concentration of CB or 6-DMAP, induced occasion, induced duration and zygote density on inducing triploid C. hongkongensis were also discussed. The results showed that:when oyster zygotes were fertilized at 28-30℃ and salinity at 15-25, and dealt with 0.50 mg/L CB began at 15-18 min, post fertilization lasted 20 min, and incubated density of zygote when treatment was about 2.0×10⁸ ind/L. These were optimum conditions under which triploid of C. hongkongensis was induced by CB. In this case, triploid yield was 100%, cleavage rate was 53.16%-63.00%, velar larvae gain was 47.32%-53.09%, the efficiency of triploid induction was 0.47-0.53, and the cost was 260 RMB/L. The surrounding when fertilization, and induced occasion was the same as those in CB, but oyster zygotes were dealt with 75-100 mg/L 6-DMAP last 20-25 min, and incubated density of zygote when treatment was about 4.5×10⁷ ind/L. These were optimum conditions of triploid of C. hongkongensis was induced by 6-DMAP. In this case, triploid yield was 62.52%-72.36%, cleavage rate was 60.00%-66.25%, velar larvae gain was 74.43%-90.00%, the efficiency of triploid induction was 0.47-0.65, and the cost was 139-185 RMB/L. Through comprehensive comparison between CB and 6-DMAP, we could draw the conclusion that 6-DMAP was more applicable in triploid production of C. hongkongensis than CB. This study provided the basic theory and practical experience for polyploidy breeding in oyster.

Abstract:The experiment was conducted to study the feasibility of the application of silkworm pupal oil to GIFT Oreochromis niloticus feed. Seven isonitrogenous and isolipidic diets were formulated by adding 5.0% silkworm pupal oil (SPO), marine fish oil (MFO), tilapia oil (TO), pork lard (PL), chicken oil (CO), linseed oil (LO) and soybean oil (SO), respectively, to the basal diet to feed tilapia[initial body weight (47.51±0.52) g]. Each treatment contained three replicates with 20 fish per replicate and fish were fed for 56 days. The results showed that the final body weight, weight gain rate and specific growth rate of LO and SO groups were significantly higher than that of SPO and MFO groups, but showed no significant differences with that of TO, PL and CO groups. Feed conversion ratio of SPO group was significantly higher than that of other groups, except that of MFO group, while protein efficiency rate showed an opposite trend. Feed intake showed the lowest value in SPO group, and highest value in SO group. TO group presented the lowest viscerosomatic index, body length/body depth and intraperitoneal fat ratio and the highest condition factor. Hepatosomatic index in PL group was significantly higher than that of other groups except LO group. Intraperitoneal fat ratio in MFO group was significantly higher than that of other groups except CO group. Compared with the other groups, SPO could reduce the crude lipid in whole body lipid and tissue and triglyceride (TG), glucose and malonaldehyde contents in serum. MFO could reduce the crude lipid in whole body and enhance the acetyl-CoA carboxylase (ACC) activity in fish liver. PL groups presented lower TG and total cholesterol (TC) contents in serum and higher carnitine acyl transferase-I and ACC activities in liver. The highest TG, TC, low density lipoprotein cholesterol (LDL-C) contents and aspartate transaminase activity were observed in serum of CO group. LO and SO could significantly increase the lipid retention ratio and crude lipid content in whole body and muscle. SO significantly increased the high density lipoprotein cholesterol (HDL-C) and reduced LDL-C and TC contents in serum. SPO, LO and SO, respectively, could significantly increase highly unsaturated fatty acids, α-linolenic acid and linoleic acid contents in fish muscle. In conclusion, although fish growth performance is affected, SPO has advantages of decreasing body lipid, blood lipid and glucose, protecting fish health, and optimizing muscle fatty acids composition.

Abstract:C-type lectin of Scophthalmus maximus (SmLec1) plays an important role in the non-self innate immune system. We analyzed the activity characteristics of SmLec1, and the effect of environmental stress on its expression and regulation, and explored its potential function and response in turbot innate immune system in culture environment. In this study, the molecular mass of the SmLec1 with recombinant protein was found to be 19 ku as shown by SDS-PAGE, and the target protein was obtained after purification. SmLec1 showed agglutination activity against Vibrio anguillarum and Edwardsiella sp. in the six kinds of selected bacteria to test SmLec1 bacterial agglutination activity. On this basis, eight sugars were taken for the inhibitory agglutination studies. Among the carbohydrates tested, lactose, D-xylose, D-fructose, sucrose and D-mannose effectively inhibited the agglutination activity of SmLec1. In physical and chemical factors (pH, high temperature), the activity of SmLec1 was inhibited at pH < 7, T > 37℃. QPCR was performed to examine the relative expression of the SmLec1 in V.anguillarum challenge, the expression level of liver was relatively increased after pathogenic stimulation, the highest at 6 h, then gradually began to decline and returned to its original level at 32 h. Expression of SmLec1 in high temperature stress was analyzed by qPCR, and results showed that the expression of liver mRNA starts to rise from 19℃, and showed a decreasing trend from 22℃ to 27℃, while expression of other tissues did not change significantly. The impact of salinity stress on expression was not significant. The study could provide a scientific basis for further study of antibacterial mechanism and immune mechanism of SmLec1.

Abstract:The purpose is to study the potential role of Litopenaeus vannamei armadillo repeat-containing protein 8 (ARMC8) in the immune response triggered by the virus and bacterial pathogens. Full-length cDNA sequence of ARMC8 gene from L. vannamei (named LvARMC8, GenBank Accession Number:KX058562) was first cloned using RACE method. The full-length cDNA sequence of LvARMC8 was 2917 bp, which contains a 50 bp 5'UTR, 822 bp 3'UTR and 2046 bp open reading frame (ORF) that encoded 681 amino acid residues. SMART analysis results showed that LvARMC8 contains six armadillo repeat (ARM) domains. Multiple alignment analysis shows that LvARMC8 shared 71% amino acid identity with Zootermopsis nevadensis, which is the highest. Phylogenetic analysis showed that LvARMC8 was clustered together of invertebrates groups and most closely related to Tribolium castaneum ARMC8, Culex quinquefasciatus ARMC8 and Papilio xuthus ARMC8. RT-PCR analysis showed that LvARMC8 was constitutively expressed in all the examined tissues with the highest expression in epithelium and lowest expression in eyestalk. Upon WSSV challenge, the expression of LvARMC8 was significantly down-regulated at 12 hpi (hours past infection) but significantly up-regulated starting at 48 hpi, reaching the peak at 72 hpi. By V. parahaemolyticus challenging, the level of LvARMC8 expression were markedly increased at all the detected time points except 24 hpi. The result suggests that LvARMC8 might take part in the innate immune response of L. vannamei triggered by pathogens.

Abstract:This experiment aimed to investigate the effects of protein and lipid levels on growth and physiological factors of Pelteobagrus fulvidraco larvae in recirculating aquaculture system (RAS). A random 2×2 two-factors animal experiment including two different protein levels (48%, 52%, P48, P52) and two lipid levels(9%, 13%;L9, L13) was used to formulate 4 trial diets. Each treatment had 3 replicates and 3600 individuals per replicate. The trial fish was P. Fulvidraco larvae at 2 day after hatching that was fed Artemia naupliias initial feeding for 1 day, and gradually transformed to trial diets. The conversion period of feed was 2 days. The research was conducted for 21 days. The results showed as follows. ① High protein and lipid level of diets significantly improved the survival rate(SR), weight gain rate (WGR) and feed conversion rate of P. Fulvidraco larvae with the univariate analysis.The double factors analysis indicated that P52L13 diet significantly increased the SR of trial fish compared with P52L9, P48L13 and P48L9 diet, and exceeded by 32.67%, 22.21% and 14.54%, respectively. The WGR of trial fishin P52L13 diet increased by 40.15% and 43.74% compared with P48L13 and P48L9 diet. P48L9 diet improved the SR by 15.83% and 7.21% compared with P52L9 and P48L13 diet, but the WGR was the lowest. ② The physiological factors results showed that the single factor (high protein and lipid level of diets) significantly improved IGF-1 and T3 levels of trial fish, and had a tendency to raise enzyme activity of digestion and absorption. Double factors analysis showed that the enzyme activity of digestion and absorption, IGF-1 and T3 levels of trial fish in P52L13 diet were higher than others. The activity of lipase, amylase and AKP of the trial fish in P48L9diet were higher than P52L9 and P48L13, but the Na⁺-K⁺-ATPase activity, IGF-1, T3 and GH levels were the lowest. ③ The new discovery of this study was that the trial fish with P48L9 diet had higher SR, feed intake, enzyme activity of digestion and absorption than P52L9 and P48L13, but the lowest WGR, growth related hormone level than others. It indicated that the lower protein and lipid level had an negative effect on trial fish growth, but benefited the survival ability when the protein to lipid ratio was appropriate. In conclusion, the change and interaction of dietary main nutrient elements affected growth and physiological factors of P. Fulvidraco larvae. This research shows that the P52L13 diet is the excellent combination giving consideration to SR, growth, digestion and absorption ability, growth related hormone level of P. Fulvidraco larvae in RAS. The P48L9 dietary combination with appropriate protein to lipid ratio can enhance the survival, digestion and absorption ability of P. Fulvidraco larvae. Therefore, the appropriate protein to lipid ratio has important significance for the survival and development of fish in the early stage.

Abstract:In order to understand further the genetic resources of Macrobrachium nipponense in South Baiyangdian (SB), North Baiyangdian (NB) and Hengshui Lake (HS) of Hebei Province, we investigated the genetic structure of Oriental river prawn M. nipponense among three different wild populations from Baiyangdian and Hengshui Lake of Hebei Province using nucleotide sequences from control region (D-Loop) gene of mitochondria. The results revealed polymorphisns at 80 nucleotide sites from an approximately 935 bp fragment of this gene region sequenced, accounting for 8.56% of all sites, of which 77 were parsimony-informative sites, the contents of A, T, G and C of D-loop were 42.65%, 36.98%, 9.08% and 11.29%, respectively, and the content of A+T (79.63%) was significantly higher than that of G+C. The fixation indices (F_ST) analyzed by AMOVA of ARLEQUIN Version 3.11 was 0.2336, which indicated that the variation percentages between and within groups were 23.36% and 76.64%, respectively. NJ phylogenetic tree of 23 haplotypes constructed by Kimura-2-parameter model showed haplotypes did not cluster in accordance with the group of haploid type, but characterized by different groups with individual interlaced form complex cluster. The mismatch distribution analysis and neutrality test demonstrated that M. nipponense has not experenced a population expansion recently.

Abstract:Feeding habit is one of the most important reference bases for making feeding strategy in fish aquaculture. During the fish seedling culture stage, the feeding amount, feeding species and feeding time which fit the fish feeding habits well will not only increase the survival rate but also improve the feed efficiency greatly. The Sebastes schlegelii is one of the most important aquaculture and enhancement fish species in China, Japan and Korea. In culture conditions, though the feeding cost is the greatest production cost during the S. schlegelii seedling culture, an excessive mortality still often occurred during the early development culturing stage due to inappropriate feeding strategy. Therefore, in order to better understand the feeding characteristics of S. schlegelii during the early development stage, the feeding habits of larvae and the gastric evacuation rate of juvenile in the condition of artificial seedling were examined by using an experimental ecology approach. Results show that S. schlegelii had already acquired good foraging capability at larvae stage. For the feeding rhythm of 2 days after hatch (DAH), S. schlegelii larvae exhibited feeding peak at 16:00, and the feeding peak of post-larvae (15 DAH and 25 DAH) was at 16:00 and 20:00. So the feeding behavior of S. schlegelii larvae mainly appeared at daytime and the feeding peak period was gradually prolonged with fish growth. The daily feeding intake rates of larvae S. schlegelii were 42.26% (2 DAH), 16.25% (15 DAH) and 13.07% (25 DAH), which could be used as a reference for daily feeding of larvae in seedling culture. The results show that juvenile S. schlegelii with different body weight (average body weight 1.78 and 8.52 g) exhibited different gastric evacuation traits at 22℃. The linear, exponential, square root and Logistic models were used to fit the gastric evacuation data and all the four models fit the data well. After a composite analysis, it can be concluded that the best mathematical model fitted to the gastric evacuation data of 1.78 and 8.52 g juveniles were the linear model and the Logistic model respectively. Through the mathematical model, it can be calculated that the gastric evacuation rate of 1.78 and 8.52 g juvenile S. schlegelii were 0.007 and 0.047 g/h respectively. Based on the gastric evacuation traits and the effect of feeding frequency on the coefficient of variation of fish body weight, it can be concluded that feeding to satiation twice or thrice per day is appropriate for 60-90 DAH juvenile S. schlegelii in the rearing practices.

Abstract:Chitin is the main component of mollusk shell organic scaffold and its metabolism is important for shell mineralization. Chitinase with the function of chitin hydrolysis plays a key role during chitin metabolism process and is related to the formation process of shell organic scaffold. In this study, by the mass spectrum analysis of shell protein, it was proved that chitinase had an abundant amount in the shell of Chlamys farreri. The cDNA sequence of gene chitinase was obtained by RACE and its full length is 1587 bp, coding 439 amino acid residues. Analysis of chitinase protein sequence with bioinformatics software shows that it has a conservative function domain existing in chitinase protein family with the function of chitin hydrolysis. Chitinase in C. farreri had a much higher expression level in the mantle tissue than in other tissues, especially the area of mantle edge. In the process of shell regeneration after shell notching, the expression level of chitinase showed a decreasing tendency indicating that chitinase responded as a negative regulatory factor during shell regeneration. After knocking down the expression of chitinase, the structure of the mineral slices was irregular and fused with a fuzzy shape and unclear boundary. In conclusion, it is suggested that chitinase in C. farreri might be related to the formation of shell organic scaffold with its function of chitin hydrolysis, which is also important during the process of shell biomineralization.

Abstract:An 8-week feeding trial was conducted to evaluate the effects of different dietary wheat starch and lipid levels on growth performance, feed utilization and hepatic glycolysis and gluconeogenic key enzyme activities of large yellow croaker. Six isonitrogenous diets were formulated to contain three wheat starch levels (5%, 10% and 30%) and two lipid levels (5% and 10%), respectively. Each diet was randomly assigned to feed three replicate groups of juvenile large yellow croakers with the initial weight of 6.75±0.12 g and fed twice daily to apparent satiation. The results indicated that dietary wheat starch and lipid levels didn't have significant influence on weight gain (WG), specific growth rate (SGR), feed efficiency (FE), survival rate (SR), hepatosomatic index (HSI) and condition factor (CF), however, viscerosomatic index (VSI) were significantly influenced by the dietary wheat starch and lipid levels. When the dietary lipid level was the same, fish fed the diet containing 30% wheat starch level had higher WG and SGR than those fed the diet containing 10% wheat starch. Glycogen content in muscle was significantly affected by dietary wheat starch and lipid levels, but hepatic glycogen content wasn't significantly influenced by dietary different wheat starch and lipid levels. When dietary lipid level was 5%, fish fed the diet containing 30% wheat starch level had significantly higher hepatic glycogen content than those fed the 10% and 20% wheat starch diets; while, fish fed the diet containing 10% wheat starch had higher glycogen content in muscle than those fed the diets containing 20% and 30% wheat starch levels. When the dietary lipid level was 10%, fish fed 10% wheat starch level had significantly higher hepatic glycogen content than those fed 20% and 30% wheat starch diets; fish fed 30% wheat starch level had significantly higher glycogen content in muscle than those fed 10% and 20% wheat starch diets. Glutamic-pyruvic transaminase (ALT), glutamic-oxalacetic transaminase (AST), total cholesterol (TC) and glucose (GLU) were not significantly influenced by dietary wheat starch and lipid levels. However, total protein (TP) and triglyceride (TG) were significantly influenced by different dietary wheat starch and lipid levels. Lipase activity was significantly influenced by dietary wheat starch and lipid levels, when the dietary lipid level was the same, the lipase activity increased significantly with the increase of wheat starch level; fish fed the diet containing 10% lipid level had higher lipase activity than fish fed the 5% lipid level diet. The interaction of dietary wheat starch and lipid levels had significant effects on pyruvate kinase (PK), while there were no significant effects on activities of glucokinase (GK), phosphofructokinase (PFK), phosphoenolpyruvate carboxykinase (PEPCK), fructose-1,6-bisphosphatase (FBPase) and glucose-6-phosphatase (G6Pase). The results showed that when the dietary lipid level was 5%, large yellow croaker had the ability to maintain blood glucose content by adjusting the hepatic glycolysis key enzymes activities with increase of wheat starch supplemental level.

Abstract:Tissue slicing and enzyme linked immunosorbent assay (ELISA) was conducted to help understand the law of development and the level of sex steriod of cultured Pampus argenteus, and we observed the developmental characteristics of testis and ovary of P. argenteus under breeding conditions and the year-round changes in serum neutral steroids. The relation between gonadosomatic index GSI, hepatosomatic index HSI, condition factor CF and gonad development were also studied. The results showed that breeding females matured at the age of 1 year, and the matured ovary presented in the shape of ">". Nearly half of individuals entered into stage III in November, 33.3% individuals had been developed into stage IV. From December to next January during the winter, about 2/3 individuals degenerated to stage II and developed quickly to stage IV in March. In April, P. argenteus reached stage V and spawned. After spawning, the ovary entered into stage IV. The structure of testis is lobule lumen, and lobular cavities appeared in stage III of testis, and sperm appeared in stage IV. The development of testis was faster than that of ovary, which means "male premature". 20% of individuals reached sexual maturity after 7 months. During the winter, from December to the next February with decreasing temperature, the testis degenerated to stage III and in March the testis developed again, sperms were discharged at different time. GSI of females differed from 0.19% to 12.89%, HSI was from 0.97% to 2.30% and CF ranged from 2.30% to 3.08%. GSI in males ranged from 0.08% to 2.62%, the value of HSI was from 0.73% to 1.83% and CF was from 2.11% to 2.80%. The value of GSI reached the maximum in the stage V, and HSI and CF reached the peak in stage IV. The content of E₂ of female varied from 23.27 to 59.13 pg/mL and the content of E₂ of male was 15.90 to 36.20 pg/mL in different develpomental stages and the value of HSI in females showed significant positive correlation. The content of testosterone (T) in female was from 14.57 to 68.67 nmol/L and that in male was 18.62 to 66.49 nmol/L in different develpomental stages and changes in expression levels of T showed significant positive correlation. Our research shows that the content of serum steroid hormones was closely related to the development of the testis and ovary and could serve as an important indicator to understand the development of cultured P. argenteus gonad in time.