Abstract:The stability of the red fluorescent protein (RFP) transgenes is important for application of the transgenic Tanichthys albonubes line.This paper investigated comparatively the inheritance and expression of RFP gene in different transgenic T. albonubes generations. Under the observation of fluorescence microscope, RFP gene was expressed in almost all body tissues, and both F6 and F10 generations had a similar expression pattern. Results of self-cross and test-cross breeding experiments of transgenic F6 and F10 individuals indicated that segregation of RFPgene still followed Mendelian single-gene inheritance, and their transgenic progenies had a uniform phenotype. The regions including myosin light polypeptide 2 promoter,RFPgene coding sequence and transgene flanking junctions were amplified by PCR from genomic DNA of F2, F6 and F10 generations. Sequence alignment analysis showed that these important regions were well preserved in transgenic fish, and any kind of alteration at nucleotide level was not found. These results suggested that, RFP gene in transgenic T. albonubes maintained stable inheritance and expression through successive generations.

Abstract:In the present study, the membrane-bound immunoglobulin M (mIgM), mIgD and secretory IgZ (sIgZ) have been identified by using RACE-PCR from the orange-spotted grouper, Epinephelus coioides. The mIgM and sIgZ are comparable with their counterparts in other teleost in terms of their heavy chain cDNA sequences and gene structures. The constant region of the mIgM had three CH domains, i.e., CH1, CH2, CH3, and two transmembrane domains, TM1 and TM2. The TM1 exon is spliced into the regular donor site at the 3’ terminus of the CH3 domain. When comparing the amino acid sequence of mIgM with those in teleost fish, it is found that the grouper mIgM CH region shares highest identity with that in the Japanese oliver flounder (Paralichthys olivaceus), with CH1, CH2, CH3 having 53% - 78% identity with those in the flounder, respectively. The complete transcript of the grouper mIgD contains 3 375 bp, including a 3 006 bp open reading frame, and the constant region of the mIgD consists serially of a μ1 domain, seven δ domains (δ1 to δ7), and a TM region. The degree of amino acid sequence identity, in domain-by-domain comparison with other teleost fishes, reveals an overall higher identity between the IgD in the grouper and that in mandarin fish (Siniperca chuatsi), with d1 to d7 having 75.5%, 75.8%, 65.4%, 76.6%, 88.1%, 90.6%, 82.8% identity, and the transmembrane domain having 82.7% identity, respectively. The sIgZ has a four exon structure in genome, with the introns being 222, 129, and 458 bp in length, respectively. The semi-quantitative RT-PCR was performed to examine the expressions of IgZ, IgM, and IgD in various organs / tissues of the grouper. Transcripts encoding the mIgM were detected in all examined samples. IgD was mainly detected in pronephros, kidney, spleen and thymus, with week expression in intestine. IgZ was expressed in lymphoid tissues such as pronephros, kidney and spleen, with relatively low expression detected in gills, thymus and heart.

Abstract:A 90 d experiment was conducted to investigate the effects of dietary natural lutein levels on growth, and body pigmentation of Pelteobagrus fulvidraco. Five experimental diets were designed with 0%, 0.15%, 0.3%, 0.6% and 8% of test compound and the highest dose was ten times more than possible dose. Five extruded pellets were determined xanthophylls dosage as non detected, 24.2, 54.2, 118 and 1700 mg/kg, respectively, which were named C, L24.2, L54.2, L118 and L1700 accordingly. Each treatment was randomly assigned four replicates with 30 fish in each tank. We found pigment inclusion did significantly enhance growth performance and feed efficiency of P. fulvidraco. Productive protein value of L24.2 group, energy productive values of L54.2, L118, L1700 groups were significantly higher than those of control group (P<0.05). Yellowness (b^*) and saturation (c^*) of lateral and ventral skin obviously increased until they reached saturation in L118, which showed no difference with L1700 group(P>0.05). Pigmentation of skin in L118 and L1700 deposited excessively and transferred into muscle. Bioaccumulation factor of skin pigment increased firstly and then decreased, the highest in fish fed 76.25 mg/kg diet. The results showed 24.2-1700 mg/kg pigment inclusion significantly improved growth performance of P. fulvidraco. The optimum concentration of pigment as a colorant in yellow catfish was 76.25 mg/kg feed.

Abstract:The technique of homologous cloning and Rapid Amplification of cDNA Ends(RACE) was used to amplify full length cDNA of immunoglobulin light chain 3 isotype (IgL3) gene from largefin longbarbel catfish (Mystus macropterus Bleeker). IgL3 in M.macropterus has 947 nucleotides, including 5￠-UTR of 58 nucleotides, 3￠-UTR of 184 nucleotides and an open reading frame with 705 nucleotides encoding a peptide of 234 amino acids. The deduced amino acid sequence contains an constant region(CL) and a variable domain(VL) consisting of 4 frame regions(FRs) and 3 complementary determining reg-ions(CDRs). The IgL3 comparison in seven teleost species showed that IgL3 in M.macropterus shared the highest identity (68.8%) with that(F) in Ictalurus punctatus, and the lowest identity(47.2%) with that in Salmo salar. Phylogenetic tree based on some teleost IgL amino acids showed that IgL3 in M.macropterus was clustered closely with that (F) of I. punctatus and grouped with IgL3 in other teleost, and was far away from L1 and L2 of teleost. Real-time PCR showed that IgL3 mRNA expression of M.?macropterus was mainly detected in head kidney, spleen and blood cells and increased significantly in these tissues after injection of Aeromonas hydrophila. The result indicated that head kidney, spleen and blood cell are main organs for IgL3 expression after stimulation, and play a critical role in immunity interaction in M.?macropterus.

Abstract:This study focused on evaluating the effects of different dietary lipid sources on growth, body composition, serum biochemical indices, and activities of lipometabolism enzymes of Carassius auratus gibelio. The growth experiment was conducted to test four dietary lipids (soybean oil, rapeseed oil, linseed oil, and fish oil) on C. auratus gibelio. The fish with initial body weight (14.33±0.02) g were randomly divided into 4 groups with 3 replicates per group, fed with 5.4% of each lipid included in basic diet in a recirculation system for 63 days. The results showed that the weight gain rate and the specific growth rate of fish fed both soybean oil and rapeseed oil were significantly (P<0.05) higher than that of fish fed fish oil, while the condition factor of fish that fed soybean oil was significantly (P<0.05) lower than that of fish fed fish oil and linseed oil, and not different from that of other groups. However, the muscle moisture, the crude lipid, the crude protein, and the ash content in different tissues of C. auratus gibelio did not showed significant difference among the groups (P>0.05). Fatty acid composition of muscle in fish generally reflected the composition of the diet. There was close correlation between the fatty acid composition of fish muscle and those of experimental diets. The activities of glutamic-pyruvic transaminase (GPT), glutamic-oxalacetic transaminease (GOT), alkaline phosphatase (ALP) in the plasma of fish oil group were significantly higher than the other groups (P<0.05), while no significant difference was found among all treatments in insulin, cortisol, total protein (TP), albumin (ALB), globulin (GLB), A/G, glucose (GLU), cholesterol (CHOL), and triglyceride (TG) in the plasma. Furthermore, enzyme activities related to lipid metabolism (carnitine palmityl transferase-I, carnitine palmityl transferase-II, acetyl-coa carboxylase, lipoprotein lipase and so on) of crucian carp were not significantly different among all treatments. These results indicate that the diet supplemented with rapeseed oil or linseed oil in feeding C. auratus gibelio can also achieve good growth and provide theoretical basis for the replacement of fish oil and soybean oil, which can economize the production cost in the future.

Abstract:Cytochrome P450c17 is one of the most critical enzymes in steroidogenic pathway, which is essential in the production of sex steroid hormone(androgens and estrogens). Up to date, there are two P450c17 s (P450c17-I and P450c17-Ⅱ) enciodedencoded by two different genes. P450c17-I possesses two enzyme activities, namely 17α-hydroxylase and 17, 20-lyase, while P450c17-Ⅱ only has 17α-hydroxylase. Under the condition of P450c17-I and P450c17-Ⅱcomplete cDNAs, the spatial and temporal expressions of the two genes are studied by the semi-RT-PCR technology, combined with gonad development and serum testosterone(T) level. The results of gene spatial expression analysis showed that tongue sole P450c17-I was distributed widely, which was expressed in testis, stomach, intestine, heart, spleen and brain, while tongue sole P450c17-Ⅱdistribution was tissue-specific, which was only expressed in testis and head kidney. During various developmental stages of testis, P450c17-I expression pattern revealed developmental stage-dependency, while the expression pattern of P450c17-Ⅱ was on the contrary. It is predicted that, during the whole reproductive period, P450c17-I regulates the sex steroid hormone on the transcriptional level or after transcription in male tongue sole, while P450c17-Ⅱmay be related to progestin in inducing spermiation and DNA replication in spermatogonia.

Abstract:Hybrid snakehead ( Channa maculata♀ × C. argus♂) is one of the most popular species cultured in the areas of eastern and southern China. With high density culture and rapid expanding production, problems of its diseases become more and more serious. A disease with white spots in internal organs of hybrid snakehead broke out in Fushan and Guangzhou in Guangdong Province in 2011. Bacteria pathogens were isolated from diseased hybrid snakehead cultured in pond. Two bacteria strains with strong virulence were chosen for identifications. The morphological, biochemical and physiological characteristics of the two isolates were studied by using conventional method, ATB Expression System(ID32 STREP)and other assays, and the characteristics of the isolated strains were in accordance with those of Aeromonas schubertii. Molecular analyses of 16S rRNA and gyrB genes were used for further identification. BLAST showed that 16S rRNA and gyrB genes of two strains possessed high similarities with their counterparts registered in GenBank and with each other. The virulent tests were carried out by using the pure culture of the isolated strains artificially infected hybrid snakehead, and the result indicated that the high concentration of bacteria (≥1 × 107 CFU/mL) caused acute death, and infected diseased fish displayed symptom of sarcoidosis after three days, while the control group showed no signs in 7d post-challenge. The morphological and biochemical characteristics of the re-isolated bacteria from the artificially infected diseased fish were the same as those of the original infected bacteria. Antibiotic sensitivity assays showed that among 16 antibiotics tested 14 were sensitive,and 2 were resistant.

Abstract:Elongation factor (EF) is a protein factor which plays roles in the peptide chain elongation in the process of protein synthesis, including elongation factor 1( EF-1) and elongation factor 2(EF-2). Elongation factor 1 consists of four subunits α, β, γ and δ, and plays a key role in protein translation process. In this study, we cloned EF-1δ gene from Eriocheir sinensis using reverse transcriptase polymerase chain reaction (RT-PCR) and rapid-amplification of cDNA ends (RACE), and primers were designed according to the conserved sequence of elongation factor-1 δ from Xenopus laevis. The full-length cDNA sequence of EF-1δ is 933 bp which codes 263 amino acid residues. And comparison results showed that the nucleotide homology of EF-1δ was 70% similar to Xenopus laevis and amino acid homology of EF-1δ was 54% similar to Danaus plexippus, using BLASTN and BLASTX software. The phylogenetic analysis based on amino acid sequence shows that EF-1 δ has highest similarity with EF-1δ of Lepeophtheirus salmonis. The expression of the gene in different tissues and stages of E. sinensis was analyzed by real-time fluorescent quantitative PCR. The result showed the EF-1δ mRNA was mainly detected in muscle and small amount in testis, hepatopancreas and trace in heart, ovary, stomach, intestine, gill. EF-1δ mRNA was detected with high level in muscles compared to hepatopancreas and gill in different developmental states of the crab, and displays significant difference at P<0.05. It also has significant difference at P<0.05 between muscles in different developmental states, and it was detected the highest expression in precocious crab, followed by mature crab and by a lower expression of crablet; And there is no significant expression difference between hepatopancreas and gill tissues in different developmental states.

Abstract:Motility is thought to contribute to the virulence of many pathogenic bacteria. Infection studies in many motile pathogens found that in many causes normal motility was required for efficient infection. However, there are few reports on the direct correlation between motility and virulence in Vibrio. In order to understand the role of motility of Vibrio alginolyticus in virulence, the mini-Tn10/Km transposon-induced mutant bank was constructed and 73 motility defective mutants were screened out by double semi-soft agar medium. After purification and repeated screening the mutant ND-01MM with stable motility defect was obtained and identified by Southern blot. The chemotaxis and adhesion of wild-type strain ND-01 and the mutant ND-01MM to mucus of the natural host Pseudosciaena crocea and their persistence in phagocytes of P. crocea were tested. The results showed that the chemotaxis and adhesion of the mutant was highly significantly impaired(P<0.01)when compared with the wild-type strain, however there was no significant difference in their ability of persistence in phagocytes(P>0.05). The results of infection test showed that the virulence of the mutant was decreased by immersion infection, but not different from the wild-type strain by intraperitoneal injection.

Abstract:A new biological preservative—antimicrobial peptide APNT-6 produced by Bacillus natto NT-6 and purified by column chromatography will be applied in the fresh-keeping of Litopenaeus vannamei. Bacillus antimicrobial peptides are a series of lipopeptides substances produced by represented Bacillus strains of B. subtilis, B. amyloliquefaciens and B. natto, which include surfactin, iturin, fengycin, subtilin and so on. Numerous studies show that Bacillus antimicrobial peptides have a startling range of antimicrobial activities that can include action against most Gram-negative and Gram-positive bacteria, fungi, enveloped viruses, and eukaryotic parasites. Recently, our research group isolated a highly antibiotic activity and largely antimicrobial spectrum strain—B. natto NT-6 from the Chinese traditional food—lobster sauce. According to the mass spectrometry (ESI /MS /CID) analysis,we know the mainly antimicrobial substances produced by this strain is Bacillus antimicrobial peptides, mainly including surfactin, fengycin, and iturin(called after APNT-6). Through oral acute toxicity in mice we found that its LD50 greater than 5000 mg/kg body weight, indicating that antimicrobial peptide APNT-6 has high food safety. In this paper, the antibacterial activities of antimicrobial peptide on spoilage organisms were determined by Oxford cup assay. Then the quality changes of L. vannamei during storage at (4±1) ℃ were investigated, including the pH, total volatile basic nitrogen (TVB-N), aerobic plate count (APC) and sensory assessment. The results showed that antimicrobial peptide APNT-6 can effectively inhibit 8 strains of spoilage organisms isolated from L. vannamei. During storage at (4±1) ℃, with the extension of storage time, the gradually increasing values of pH, TVB-N and APC of L.vannamei were observed during the 7 days storage. However, incubated 0.5 mg/mL antimicrobial peptide can effectively slow down the value increasing, which extends the shelf-life of L. vannamei by 2-3 days.

Abstract:In this study, total 35 microsatellite DNA markers were selected to analyze the genetic structure of 110 individuals in an F2 family which is obtained by directional mating techniques for the selective program on fast growing Portunus trituberculatus. (The F2 family was created by F1 family which was generated by wild populations from Laizhou Bay and Zhoushan Island.) The results showed that total 87 different alleles were found, and the number of alleles was 2 to 4 in each locus, with 2.2 effective alleles on average. The value of mean observed heterozygosity, the value of mean expected heterozygosity and the mean Polymorphism Information Content (PIC) was 0.646 5, 0.513 0 and 0.449 1, respectively. The probability value of chi-square test showed that most of the loci deviated from Hardy-Weinberg equilibrium significantly. The GLM procedure in SAS9.1 was used to analyze the correlation between these 35 microsatellite markers and growth related traits of P. trituberculatus. The growth related traits included full carapace width, body weight, carapace width, carapace length, body height, second obital margin width, meropodit length of the claw, meropodit length of the first peraeopod. Results indicated that Pot08 had a significant impact on full carapace width, body weight, carapace length, body height, second obital margin width; Pot42 had a significant impact on body weight, carapace length, meropodit length of the claw, meropodit length of the first peraeopod; Pot53 had a significant impact on carapace width and meropodit length of the claw, and had a very significant impact on second obital margin width; Pot57 and PTR30 had a significant impact on meropodit length of the first peraeopod and carapacel length, body weight, respectively; PTR8a had a significant impact on the first peraeopod and carapace length, body height, and had a very significant impact on body weight, second obital margin width, full carapace width and carapace width; PTR131 had a significant impact on body weight, full carapace width and carapacel width. Finally, PTR8a can be used for marker assisted selection which could be used for body weight selection.

Abstract:The aim of this work was to study the effect of adding silver carp surimi on dielectric properties and gelatinization characteristics of wheat flour heated by 150 W microwave oven operating at 2 450 MHz. Wheat flour and silver carp surimi were mixed in various proportions (10:0, 9:1, 8:2, and 7:3) at moisture content of 38 wt.% with 2 wt.% salt. Then, the mixtures were formed to three different sizes and two different shapes to investigate the effect of geometry on uniformity of temperature distribution under microwave heating. The dielectric properties of silver carp surimi-wheat flour dough were detected by the open-endedcoaxial probe method. Differential scanning calorimeter (DSC) was conducted to determine the extent of gelatinization of wheat starch. It is observed that the uniformity of temperature distribution for cylindrical-shaped pieces of dough was better than cuboid ones and the smaller ones were better than bigger ones. When temperature increased, the dielectric constants and loss factors of all dough tend to decrease. As silver carp surimi was added, the uniformity of temperature distribution was improved, however, the activation energy of sample decreased. The gelatinization rate of starch decreased with temperature rise and addition of silver carp surimi as a result of interaction of surimi and water.

Abstract:The inter-simple sequence repeat(ISSR) was conducted to analyze the genetic variation of four native populations of Trachidermus fasciatus in China - Zhejiang population(Z), Shangdong population(S), Hebei population(H) and Yalvjiang Yalujiang population(Y), with 15 polymorphic primers selected from 100 ISSR primers. For each population, 30 samples were used in the study. Six to seventeen bands were amplified for each primer. Altogether, 181 useful loci were detected and out of them, 136 ones were polymorphic, accounting for 75.14%. Among the four populations, H population had the lowest effective allele number (1.258 5), Nei’s gene diversity(0.153 0), Shannon’s information index(0.232 2), and polymorphic loci percentage(49.17%), while Y population’s indexes (1.479 4, 0.277 7, 0.411 2, and 74.03%, respectively) were the highest. The corresponding values of Z and S populations were higher than those of H population and lower than those of Y population. Taking the four populations as a whole, the total Nei’s gene diversity and Shannon’s information index were 0.269 1 and 0.400 9, respectively, showing a relatively high diversity of T. fasciatus. The values of G_ST and N_m were 0.131 3 and 3.309 4, indicating medium differentiation and some degree of gene exchange that existed among the populations. As results of AMOVA indicated, there were 85.54% variation that existed in the individuals and 14.46% variation among populations. At the same time, there was significant differentiation among the four populations (P<0.05 or P < 0.01), too. In the UPGMA tree conducted on the genetic distance, Z and S populations clustered firstly, then with Y population, and finally joined to H population. Obviously, the Z, S, and Y populations had a relative close relationship according to their geographic distance, whereas H population showed clear divergence from the other three populations.

Abstract:It was well known that aquatic products collected from different locations might considerably differ in their types and quantities of nutrient components, therefore, resulting in different quality. It is generally believed that these differences are essentially caused by various environmental conditions and habitats where the aquatic products are grown and harvested. SoTherefore, the quality control of aquatic products was a major concern for both the health authorities and the public. Hence, a validated method was essential for a quality assessment point of view. Because of its advantages and popularity, fingerprint analysis was widely accepted and used in quality control systems of herbal medicines, and some methods have been proposed for the fingerprint analysis, including infrared spectrum (IR), gas chromatography (GC), high-pressure liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS); but fingerprint technology was rarely used in the quality control of aquatic products at present. For the first time, a validated infrared spectrum method coupled with cluster cluster analysis, principal component analysis and load factor analysis methods had been developed for the study of the infrared fingerprint of mussel, and Fourier transform infrared (FTIR) spectrometer was performed on the 24 batches samples collected from Dalian, Yantai, Qingdao, Zhoushan, Xiamen and Haikou. Similarity analysis results indicated that similarity of 21 batches samples was higher than 0.9, which accords with the fingerprint technique criterion. The samples from the same region had the similar characteristic peaks of infrared spectra and could be clustered together. The normalized spectra was selected to construct principal component analysis model in the range of fingerprint region 1 800-800 cm^-1, and according to the model, the first two principal components (PC1 and PC2) accounted for 96% of the variance information in the fingerprint region, and each sample was able to form distinct ccluster in the principal component space, then the identification of mussel from the six regions was basically achieved. Besides, to some extent, the sparse density of the samples distribution reflected the genetic relationship. The loading factors of the model were analyzed, and the results indicated that the differences between mussel samples mostly depended on the contents of unsaturated fatty acids and phosphatides. The contents of unsaturated fatty acids in mussel from Haikou and Xiamen were highest in all samples, and the contents of phosphatides in mussel from Dalian and Yantai were highest in all samples. On the whole, FTIR combined with cluster analysis, principal component analysis and load factor analysis provided an effective way to identify the regions of mussel rapidly and nondestructively, and could detect the unsaturated fatty acids and phosphatide contents in mussel from different areas.

Abstract:Age and growth are two important biological characteristics of cephalopoda. According to the 3462 short-fin squid Illex argentinus samples collected by the Chinese jigging fishing fleet during 2007, 2008 and 2010, the age, growth and population structure of Illex argentinus were studied based on the microstructure of the statolith. The result indicated the life cycle of Illex argentinusis approximately one year, two hatching groups could be identified (austral winter group and austral autumn group), and there was a sexual dimorphism in the mantle length and body weight growth between different groups. The relationship between age and mantle length (ML) was best described by exponential and linear functions for females and males for austral winter group and exponential and logarithm functions for austral autumn group, respectively. The relationship between age and body weight (BW) was best described by exponential and logarithm functions for females and males for both two groups. The instantaneous relative growth rate of Illex argentisnus tended to be high at young stages, and then decreased with the age increasing, however the absolute growth rate tended to be higher with the age increasing, and the growth rate was different between males and females in the same age stage.

Abstract:The process of gonadal development and differentiation of large yellow croaker Larimichthys crocea was investigated with histological methods. The sampled fries were hatched on Sept. 22nd , 2009 at 26℃. The temperature for nursery and culture were 22.0 ℃ - 25.8 ℃ and 11.5 ℃ - 25.6 ℃, resepectively. At the age of 20 days post hatch (dph ), when the fries gained 17.6 mm - 19.2 mm in body length (BL), a pair of primordial gonads were present in the abdominal cavity. Ovarian differentiation occurred at 55 dph (BL 27.5 mm - 37.0 mm), and was characterized by the presence of clusters of oogonia. The formation of ovarian cavity and meiosis of germ cells began simultaneously at the age of 60dph (BL 28.0 mm - 37.2 mm). The presence of primary oocytes occurred at the age of 120 dph (BL 39.2 mm - 51.0 mm). The differentiation of testis began at the age of 95 dph (BL 38.0 mm - 48.0 mm) and was characterized by the presence of efferent duct and the scattering of somatic cells throughout the gonad. Cyst of spermatocytes could be seen at 215 dph (BL 44.0 mm - 59.2 mm) and testis lobules started to form at 230 dph (BL 56.2 mm -72.8 mm). These results suggested that large yellow croaker is a differentiated gonochorist, and differentiation of the ovary occurs earlier than that of testis.

Abstract:Based on the analysis of Maurolicus muelleri (Gmelin, 1788) larvae and juveniles samples col- lected during the oceanographical expedition cruises which were conducted in central and western tropical Pacific and the Kuroshio extension regions in the East China Sea, from April to June during 1978 to 1986, and combined with the related literature, this paper described the morphological characteristics of the eggs, larvae and juveniles of M. muelleri in detail. It aims to enrich the knowledge on the early life history stage of fishes in China and to provide available information to resolve taxonomic problems of this specie. The egg of the M. muelleri is buoyant, colorless, and spherical in shape. The egg membrane is uniquely sculptured, with the envelope considerably thickened and drawn up into hexagonally arranged points. The diameter of the egg ranges from 1.29 to 1.82 mm. And the inner diameter of the egg envelope ranges from 0.87 to 1.17 mm. The egg has a single oil globule measuring 0.22 to 0.28 mm, and with a narrow perivitelline space. The yolk is coarsely segmented. The pigmentation was lacking on the embryo during the embryogenesis. Prelarva, 2.80 mm in total length (TL): the anus was located just behind the yolk sac, somewhat posteriorly to the middle of the body. The number of the myomeres was 17+16=33. The pigmentation was still lacking on its body. Prelarva, 2.90 mm in TL: the melanophores begin to scatter on the optic vesicle. Postlarva, 5.90 mm in TL: the air-bladder well developed with its upper posterior part scattered with pigment spots. Postlarva, 6.90 mm in TL: 2 BR and 2 IV₂ photophores were apparent. Postlarva, 8.20 mm in TL: the black pigment spots on the upper posterior part of the air-bladder were becoming increaseingly pigmented. Otherwise, 3 BR, OP₃ and 7 IV₂ photophores were apparent. Juvenile, 10.70 mm in TL: a pigment stripe was scattered on central of the ventral sac. The number of BR and IV₂ photophores increased; otherwise, 1 ORB photophore was apparent. Juvenile, 14.00 mm in TL: some black star-shaped pigmentation that varied in size were scattered on the dorsal surface of its body from the top of the head to the caudal peduncle. Dense melanophores on the caudal peduncle were observed. The entire ventral sac was scattered with black pigment spots. OP₁, OP₂, 5 IV₁, 5 OA, 4 VAV, 6 AC₂ and 6 AC₃ photophores were apparent. However, till then the photophores system has not well-developed.

Abstract:At present, the cultivation of sea cucumber in China is mainly concentrated in the north. The main rearing species is Apostichopus japonicu. However, in the southern part of china China , the high temperature of water is not fit for the cultivation of A. japonicu. As a result, to meet market demand, developing the cultivation of tropical sea cucumber is very necessary. Holothuria scabra is one of common tropical sea cucumbers with high economic value in Hainan. In this thesis, to enhance the seeding technology of H. scabra, the embryonic and larval development of H. scabra was observed and recorded. The heights of fertilized eggs, embryos and larvae were measured under the light microscope, and the time series table of embryonic and larval development was confirmed. The results show that the bloodstocks were spawned artificially by using the method of streaming and drying in the shade jointly. A large number of fertilized eggs were gathered and the fertilized rate was over 90%. The embryonic and larval development of H. scabra can be divided into the following stages: fertilized egg, cleavage, blastula, rotary blastula, gastrula, early auricularia, mid auricularia, late auricularia, doliolaria, pentactula and juvenile. At the average temperature of 29 ℃ and salinity of 34, the fertilized eggs needed 3 hours to develop to the blastula, and 4 hours to the rotary blastula, 5 hours to the gastrula, and 19 hours to auricularia. Then it took about 7 days to develop to the doliolaria and 15 days to develop to juvenile sea cucumber. Through the observation, the conclusion can be drawn that the polyspermy can make the embryo become developmental abnormal. In the end, the development ceased and the creature died. The sizes of larval arms and the appearance of globoid at the big auricularia stage can be used as the important indexes for evaluating the healthy status of the larva of H. scabra. The bigger the larval arms , the higher the appearance rates of globoid were, the higher the metamorphic rates and survival rates of the larva were. Through the comparison with larvae of other kinds of sea cucumbers, the conclusions are obtained that there is a salient structure at the end of larval body of H. scabra, but A. japonicus and Australostichopus mollis have no such organ; while the difference gives rise to the result that the sites of ossicles of different kinds of sea cucumbers are not the same. And, the schedules of the embryonic and larval development are different from H. scabra to other species of sea cucumber. The research could provide dependable data, photos, measures of disease control for the H. scabra larva cultured production to contribute to the exploitation and development of aquaculture of southern sea cucumber. So the market demand could be met and the natural resources could be protected.

Abstract:An experimental study of co-culture of sea cucumber Holothuria leucospilota with the Pacific white shrimp Litopenaeus vannamei was carried out in the laboratory. Results indicated that nutrient structure of the culture system was influenced significantly by the sea cucumber: the phosphate and nitrate concentrations were enhanced more obviously in the co-culture system than the monoculture system, and by contrast, the ammonium concentration was kept low in the co-culture system. The organic and sulfide contents of the sediment were reduced in the co-culture system, the sulfide content in the co-culture system was (7.71±1.33) mg/kg, accounting for only about one-third of the value of the monoculture system. Co-culture of sea cucumbers had positive effect on the growth and survival of shrimps, the specific growth rate of the shrimps in the co-culture system was (0.69±0.13) %/d, which was significantly higher than that of the monoculture system[(0.45±0.06) %/d]; the survival rate of the shrimps in the co-culture system was 72.5%±22.9%, which was significantly higher than that of the monoculture system 55.0%±17.5%. In the co-culture system, the shrimps had no negative effect on the sea cucumbers, and the sea cucumbers could ingest and assimilate the sediment in the culture system efficiently (with an assimilation efficiency of 36.36%±13.79% for organic matter in ingested sediment). Co-culture of sea cucumber H. leucospilota in the shrimp culture system has both environmental and economic benefits. This co-culture method could contribute to the sustainable development of aquaculture in China.

Abstract:Stocking density is a crucial factor involving in aquatic productivity. This paper evaluate the effects of stocking density on growth, digestive enzyme activities and biochemical indices of juvenile Procambarus clarkii, whose initial average body weight was (0.015?0.004) g. A 30-day rearing experiment was conducted in the stocking densities of 50, 100, 300, 600, and 900 individuals/ m2,. Results showed that the final body weight of juvenile Procambarus clarkii decreased with the increasing stocking density. The activities of pepsin, tryptase, and amlase presented the reduced trend with the increasing stocking density, while cellulase, lipase, and the content of moisture were indistinctly changed (P > 0.05). The content of crude protein increased from 54.02% to 60.75% (P < 0.05), and also, muscle concentrations of triglyceride, total protein, urea nitrogen, and cholesterol increased (P < 0.05) with the increasing stocking density, while the content of crude fat decreased from 26.19% to 19.19% (P < 0.01) , and concentration of glucose in muscle in the same manner. Increasing trend of hepatopancreas concentrations of glucose, triglyceride, total protein, and urea nitrogen with the increasing stocking density were observed. These data indicate that high stocking density exerts a negative impact on the growth and digestive enzymes of juvenile Procambarus clarkii, and could altered the contents of protein, fat, glucose, and urea nitrogen .

Abstract:Eogammarus sinensis was reared at different temperatures, and salinities so as to analyze the effects of temperature and salinity on its hatching, survival and growth. E.sinensis were sampled from Haiyang shrimp cultural pond, Yantai city. The berried females were accustomed to the experimental conditions gradually as the females were pregnant. In the temperature experiment, the larvae were reared in beakers (the cubage of each was about 700 mL) at four temperatures (15, 20, 25, and 30℃). The results showed that the optimum temperature to the hatching was 20℃. The DG (daily growth) and the SGR (specific growth rate) of E.sinensis were significantly affected by temperature (P<0.01). The body length and body wet weight increased ranging from 15℃ to 25℃, and 25℃ was the optimum temperature to the larval growth. When the temperature is beyond 26, the growth was decreased. The above results suggested that E.sinensis was able to have higher biomass and productivity ranging from 20℃ to 25℃. According to correlation equations and calculation results, optimum incubation temperature is 21.50℃.On the other hand, the survival rate of larvae had no significant differences affected by temperature (P>0.05). In the salinity experiment, the animals were reared in the same beakers at seven salinities (5, 10, 15, 20, 25, 30 and 35). The number of larvae and the survival rate were both increased at first and reduced later in succession, so did the DG and SGR. There were no significant effects of salinity on the hatching, larval survival rate, the DG and SGR (P>0.05). Temperature and salinity interaction experiments showed that the E.sinensis had better ability to adapt to salinity, the development of its population was more affected by temperature than by salinity.