Abstract:Based on clearing and staining method, morphological characteristics of the early skeleton development in relation to their feeding habit were observed in Miichthys miiuy larvae. Ossification started upon the 4th day after hatching at 3.0 mm BL (body length). Hyoid arch elements were cartilaginous in 3.0 mm BL and became ossified in 7.8 mm BL, whereas interhyal retained cartilaginous condition. Also Branchial arches were cartilaginous in 3.0 mm BL and then ossified gradually. In suspensorium, not only hyomandibular, symplectic, palatine and pterygoid were earlier occurred cartilaginous than quadrate, metapterygoid and endopterygoid but also ossified early. Opercular apparatus, jaws showed a different developmental style. They started from fibrous to full ossified bone. Up to the 34th day (7.8 mm BL), most of skeleton elements became fully ossified besides quadrate, metapterygoid and endopterygoid. These results showed that the osteological development had completed in the early stage of Miichthys miiuy. The short period of ossification process showed that it had the ability to early feeding.

Abstract:In recent years, the protein hydrolysates which come from aquatic organisms, especially from marine organisms，have been known and accepted widely due to their special functionality, however, they often have the unpleasant color and odor. Researchers have been working hard in order to look for the better way to remove the unpleasant color and odor and protect the functional material as much as possible at the same time. The enzymolysis liquid with high hydroxyl radical scavenging activity was gotten from waste of seafood. The waste of seafoods is rich in collagen and hydrolyzed by marine alkaline protease 894. In order to determine the better way to decolorize and deodorize, comprehensive value has been adopted by the formula of “comprehensive value(Y)=sensory value×0.6+activity recovery×100×0.4”. The decolorization and deodorization effect on the enzymolysis liquid has been investigated with the six factors such as reaction temperature(X₁), pH(X₂), reaction time(X₆) and the amount of active carbon(X₃), β-cyclodextrin(X₄), yeast(X₅) through linear regression orthogonal design. Analyses are carried out based on F-test and t-test. Results show that both the temperature from 30 to 50 ℃ and the amount of active carbon from 0.5% to 1.5% were insignificant（P>0.05）, though the comprehensive value increases with the increasing of the factors value. The pH value was highly significant（P<0.01）from 4 to 6, and the comprehensive value decreased remarkabaly with the increasing pH value. The amount of yeast was significant（P<0.05）from 0.1% to 1.1%, and the comprehensive value decreases with the amount increasing. Both the amount of β-cyclodextrin from 0.1% to 1.1% and action time from 30 to 70 minutes were all insignificant（P>0.05）. Among the possible interactions, the interaction of the pH and the amount of yeast was significant（P<0.05）in their data zone, the comprehensive value becomes higher with decreasing of pH value and the amount of yeast. Through the regression equation and results analysis the optimum conditions were obtained: 37 ℃, pH 4.0, active carbon 0.8%,β-cyclodextrin and yeast 0.1% respectively，reaction for 30 minutes. Under theses conditions, the comprehensive value is 90.90, the protein recovery is 98.02%, the IC₅₀ concentration of hydroxyl radical scavenging had been changed to 1.62 mg·mL^-1 from 1.42 mg·mL^-1. More properties need to investigate deeply.

Abstract:To establish the changes which during embryogenesis and early larval development, fertilized eggs and larvae of Pelteobagrus fulvidraco were examined for lipid content and fatty acid compositions. The lipid content and fatty acid composition in the fertilized eggs and larvae which did not feed for 7 days after hatching were analyzed by means of common chemical assay and gas chromatography (GC). The results showed that the lipid content of fertilized eggs tended to increase during hatching period. Fertilized eggs contained more polyunsaturated fatty acids (PUFA) and monounsaturated fatty acids (MUFA) than saturated fatty acids (SFA). There was no significant change in the proximate fatty acid composition of eggs during hatching. The lipid content of larvae decreased sharply after hatching. Total lipid decreased from 4.57% on day 0 to 0.75% on day 7. The fatty acid composition in starved larvae changed significantly as starvation progressed. In starved larvae the MUFA content decreased significantly and the greatest decrease occurred in the C18:1 content. In this regard the degree of decreases was, n-9> n- 6> n-3, suggesting that MUFA were a major energy source for starving Pelteobagrus fulvidraco larvae, DHA and AA were conserved in preference to EPA.

Abstract:The tiny heat probe test system was used to determine the thermal conductivities of Muraenesox cinereus to solve the data scarcity of thermal parameters of aquatic products at different temperatures (from -30 to 20 ℃). It was convenient, easy to handle, required less time(<40 s), caused a little temperature rise(<2 ℃) of the tested sample and was suitable for measuring thermal conductivities of sample with true states. And then the thermal conductivities of Muraenesox cinereus were measured at 20 ℃、10 ℃、0 ℃、-10 ℃、-20 ℃ and -30 ℃ in detail. The results showed that the thermal conductivities of Muraenesox cinereus pre or behind phase transition can be obtained with the high precision by means of the tiny heat probe test system at different temperatures. Temperature had a significant influence on the thermal conductivities of Muraenesox cinereus. The thermal conductivities increased with temperature over the freezing point. The thermal conductivities rapidly increased below the freezing point and it increased with the temperature decreasing. And these studies may give some help to the engineering calculations and computer simulation in the course of freezing and thawing of Muraenesox cinereus.

Abstract:Porphyra haitanensis is a unique seaweed species that grows in South China and has the highest production (by weight) in Chinese aquaculture. However it has been a great loss in nori farming due to the degeneration of the germplasm quality in the last years. In order to understand the genetic bakground of P. haitanensis and guide its genetic breeding and germplasm resource protection, Inter-simple sequence repeats (ISSR) markers were used to investigate the genetic variations within and among 3 populations (PT, NR and DS) of P. haitanensis. The thalli samples were collected from 60 individuals. 15 ISSR primers gave rise to 222 discernible DNA bands of which 186 (83.78%) were polymorphic, indicating a considerable genetic variation at specific level. At the population level, the percentage of polymorphic bands (P) was from 80.18% to 81.53%, 80.93% on average. Expected heterozygosity (h) and Shannon’s information index (I) were 0.3304 and 0.4834 respectively at specific level, 0.3809 and 0.4551 at population level. According to the value of G_st, a large proportion of genetic variance (93.5%) of P. haitanensis was among individuals within population, only 6.5% genetic variance was among populations, the results indicated that the genetic differentiation level among the 3 populations of P. haitanensis was low. And according to the value of N_m, the reason of the low genetic differentiation level among populations of P. haitanensis was the sufficient gene flow. UPGMA cluster analysis based on Nei’s genetic distance showed that the individuals from the same population were no grouped together, but randomly. At Last, the necessary of protecting the germplasm resource of P. haitanensis also was discussed.

Abstract:Based on the data collected by National Tuna Scientific Observer's Program in the west-central Indian Ocean during December 2003 to June 2004 and September to December 2005, the paper preliminarily analyzed diet composition and its variation over months and fork length, feeding intensity and food items'niche breadth of yellowfin tuna Thunnus albacares by using the two-way contingency table test and one-way Analysis of Variance. The results indicated that diet compositions of T. albacares included Alepisaurus, Scomber, Nautilus, Katsuwonus pelamis, Sardinaa, Octopus, Trachurus, shrimp, crab, squid and other fishes, with squid, Scomber and crab as the main diet item according to the percentage of occurrence. Over 70% of ingestion rates for all fork length classes of T. albacares sampled were found during most months of a year. Food item replacement rates of T. albacares were below 50% year round excluding February and June and below 40% for 106-155 cm fork length class. Significant difference in feeding intensity of T. albacares appeared between months, but non-significant difference occurred among the fork length classes. Significant difference also indicated between monthly stomach fullness indexes. Significant changes in diet compositions of T. albacares were found among both months and fork length classes. Squid, Scomber, and Mautilus were fed as the main food by all fork length classes T. albacares. Monthly Shannon-Weiner diversity index of diet composition of T. albacares varied greatly and significant T. albacares maintained at the level of 0.80-1.00 and asignificant difference between the indexes appeared. Big variation of Shannon-Weiner diversity index of diet composition of T. albacares occurred to all fork length classes. Significant differences can be found in Shannon-Weiner diversity index and Pielou's evenness index of diet composition of T. albacares among both months and fork length classes. It is the first time for our Chinese scientists to attempt the feeding habits analysis of T. albacares in the western and central Indian Ocean due to the limitation of sample size, sampling period (less than one year) and lack of experience in identifying food items, the authors only focused on the feeding habits analysis of T. albacares in the western and central Indian Ocean in preliminary way, further research should be carried out on the position of T. albacares in the marine ecosystem and the food relations between T. albacares and other tuna species and pelagic species.

Abstract:Icthyoplankton composition, distribution and dominance in the Oujiang estuary （Zhejiang Province） were investigated June-September of 2007. Eggs and larvae of 18 species representing of 6 orders and 11 families were identified and counted. Clupeiformes and Mugiliformes orders had the most species. In June, most abundant larvae were Gobiidae sp. and Johnius belengerii which together made up 91.33% of total larvae. These dominant larvae were resident species and the diet for some economical fish. Yet in September, Pennhia argentatus and Gobiidae sp. were the most abundant larvae which contributed to 69.56% of the total larvae. Pennhia argentatus was important economical species in the studied area. The major spawning ground located in the waters off the Damen Island in June, the main spawning period. However, in September the spawning ground mainly located in the east waters of the Dongtou Islands. The runoff from Oujiang, the latitude, the background of topography and geomorphy, the hydgological features and its nutrients of waters from numerous islands, narrow water channels, dense reefs and the cross of fresh water and marine water are all responsible for the ideal spawning and nursery ground near the Oujiang estuary.

Abstract:In a polyculture system，sea urchin（Strongylocentrotus intermedius）juveniles weighing (1.4±0.6) g were stocked into 16 plastic tanks of each 45 cm×31 cm×30 cm at a rate of 11 individuals per tank and polycultured with juvenile sea cucumber (Apostichopus japonicus Selenka) averaging (3.4±0.6) g in body weight at a rate of 0 (Group A), 3 (Group B), 5 (Group C) and 10 individuals (Group D)，and manila clam (Ruditapes philippenarum) averaging (12.4±1.7) g in body weight at a rate of 6 individuals per tank at water temperature of 13.8-20.0 ℃ for 77 days. The sea urchin were ad libtum fed kelp (Laminaria japonica) and the sea cucumber fed marine benthic diatoms cultured by the effluents from the tanks. Survival rates of the sea cucumber and the sea urchin were all found to be almost 100%, no significant differences (P>0.05). However, there were significantly 9.12%, 7.24% and 10.06% higher in specific growth rate (SGR) of the sea urchin in Group B, Group C and Group D than that in Group A (P<0.05), respectively. There was significant lower feed conversion ratio（FCR）of the sea urchin in the polycultured tanks than that in the monocultured tanks (P<0.05), 20.2%，15.5% and 18.0% lower in Group B, Group C and Group D than that in Group A, respectively. The optimal ratio of sea urchin to sea cucumber was 11∶3, with the optimal stocking density of 64 121.1 g·m^-3 sea cucumber. Poor growth and high mortality were observed in manila clam in the polyculture system and in sea lettuce Ulva lactuca cultivated by the tank effluents. Nitzschia sp. and Cocconeis sp. were predominantly found in the benthic algae cultivated by the effluents from the tanks. The sea urchin in the polycultured tanks had significant higher gonadal C18:3n-3 and EPA+DHA levels and n-3/n-6 ratio than those in the monocultured group had. In the polyculture water, ammonia－N levels were registered low and constant, whereas high dissolved oxygen levels were observed in the polyculture system.

Abstract:The techniques on the regulation-controlling the recirculation water of indoor industrial culturing of Penaeus vannamei were studied making use of the system of circulating water treatment. This system mainly consisted of ozonator, air-liquid mixer, air compressor, foam separator and rough filter etc. The initial water before culturing and the recirculating water from shrimp culture pond before every recirculation treating during the culture experiment were treated for 4 h, then aired for 2 h in the sterilizing pond with only ozone. About 99.3% bacterial total was sterilizing and vibrio total was smaller than 1 cell·mL^-1 by such treating initial water. The culture pond water during the culture was recircularly treated for about 12 h at 4-6 d intervals with the system of the circulating water treatment in order to remove NH₃-N_t, NO^-₂-N, organism, suspended matter and bacterial etc. The frequency of using foam separating and rough filter to treating recirculation water was increased and pH was regulated with caustic lime water according to the quality of recirculating water after culturing for about 60 d. The quality of recirculating water was effectively controlled by the system of recirculating water treatment. The quality criteria of the recirculation water for use as the shrimp culture was controlled within suitable range without using any medicine and water exchanging during culture period for128 d. The average values of main parameter were as follows: turbidity 13.9 NTU，pH 8.08, oxidation-reduction 399 mV，NH₃-N^t（NH₃-N_m）0.267 mg·L^-1 (0.013 mg·L^-1)，NO^-₂-N 0.203 mg·L^-1，COD_Mn 10.34 mg·L^-1. The average body weight of harvest shrimp 13.56 g，survival rate 59.6%，yield in per cubic meter water 4.27 kg·m^-3, bait coefficient 1.01. The mode on regulating-controlling recirculation water for indoor industrial culture of prawn is proposed according to the experiment result and culturing character of Penaeus vannamei.

Abstract:Using a new hybird [NEW GIFT Nile tilapia (Oreochromis niloticus)♀× blue tilapia(O. aureaus)♂, short term JA] and closed hybrid (common Nile tilapia ♀× blue tilapia♂, short term AN) as well as their parents(GIFT Nile tilapia, short term XJ; common Nile tilapia, short term NL; blue tilapia, short term AL) as study materials, their genetic variations were studied by RAPD and SSR technologies. By RAPD:①Percentage of polymophism loci（P）-JA（20.4%）>XJ（18.5%），but < AL（21.4%）I_p)-JA（0.9086） AL（0.8895）>NL（0.8588）>AN（0.8069）；③Shannon diveristy index(H_o)-JA(0.1326)>XJ（0.1103），but < AL（0.1514）I_pop)-JA-AN (0.9444)< JA-NL(0.9496) JA-AL（0.9383）.By SSR:①Average effective numbers of alleles（N_e）-JA(2.43)>XJ(2.31)>NL（1.94）>AL（1.18），but < AN（2.82）；②Average heterozygosity（H）JA (0.700) > NL（0.570）>AL（0.497）>XJ(0.398)，but< AN (0.816)；③ polymorphism imformation content（PIC）-JA（0.661）>NL（0.568）>AL（0.513）>XJ（0.420），but < AN（0.692）；④The Nj and UPGMA tree based on genetic distance showed that, AL goes to one branch seperately, JA etc. 4 genotypes run togather into a branch. In general, the information by RAPD and SSR all revealed that, the hybrid, never mind JA or AN, all closed to their mother side, which is coincident with the our previous study results from morphology and growth.

Abstract:Effects of pH on iontransporting enzyme activities (total ATPase, Na⁺-K⁺-ATPase, V-ATPase and HCO₃^{--ATPase) and survival, growth of Marsupenaeus japonicus postlarvae were investigated. It suggested the osmoregulatory adaptable parameter of postlarvae in pH changing in view of osmotic physiological mechanism and provided the scientific basis of regulation for shrimp aquacultural systems. The results showed that the activities of ATPase, Na+-K+-ATPase, V-ATPase, and HCO₃--ATPase were obviously affected by pH variation（7.1、7.6←8.1→8.6、9.1）, which also had significant effect on its survival rate and weight gain (F＞F_0.05). Within 72 h of pH changing, the activities of ATPase, Na+-K+-ATPase in each treatment group showed peak change with the sampling time, reached theirs climax at 24 h, and stabilized after 72 h, the ATPase activity showed negative correlation with pH, while the activities of Na+-K+-ATPase came back to the level of the control group; meanwhile the activities of V-ATPase、HCO₃--ATPase of postlarvae changed increasingly within 24 h and stabilized afterwards, the activities of V-ATPase and HCO₃--ATPase showed negative relation with pH. In the range of experimental grads, the treatment of pH 7.6, 8.6 had no obvious difference with control ones in postlarvae survival rate, and the treatment of pH 8.6 also showed similar condition with the control group in weight gain. It suggested that the changing scope of pH in Marsupenaeus japonicus postlarvae culturing should not over 0.5.}

Abstract:Japanese flounder (Paralichthys olivaceus) is a widely cultured marine fish species in China and is high valued because of its fast growth and good taste. However, diseases of the cultured fish have occurred frequently and losses due to infectious diseases limit profitability and development of aquaculture. To breed new flounder strain with enhanced disease-resistance and growth rate is an important task in marine fish aquaculture. In the present study, 94 disease-resistant individuals selected from natural selection and artificial challenge by pathogenic bacteria, Vibrio anguillarum, were used as one of basic populations for developing family. Japanese population of the flounder were imported from Japan in 2003 and used as one of basic populations. In addition, the flounder captured from Yellow sea were used as one of the basic population for developing family. Different mating of the above three populations resulted in 63 families in which 54 families are half-sibling family, 9 families are full-sibling families. Growth comparison demonstrated that there are big differences in growth rate among the 63 families. Some families exhibited fast growth while some families grow very slowly. Among the 63 families, 4 fast-growth families (Family 36, 42，43 and 57), 9 secondly fast-growth families（Family 27、28、35、39、41、51、60、65 and 76）, and one slow-growth family (75) were identified. Bacterial challenge experiments demonstrated that there are big differences in disease resistance among the 59 tested families. Some families exhibited strong disease resistance to bacterial infection, while some families are not resistant to bacterial challenge. Among the 59 families, 3 families (Family 50,61 and 68) with strong disease resistance with a survival rate of over 60% were identified, 17 families with secondly strong disease resistance with a survival rate of 39%-60%, 33 families with normal disease resistance with a survival rate of 17%-39%, and 6 families with low disease resistance with a survival rate of less than 17% were identified. Development of the 63 families lay foundation for selective breeding of flounder stains with fast growth and disease resistance.

Abstract:The viability assessment of spermatozoa in the swimming crab Portunus trituberculatus was carried out by means of the traditional biostaining techniques of trypan blue and eosin B and the method of artificial induction of acrosome reaction. With the trypan blue staining，we could not differentiate clearly between the dead and live spermatozoa. But we could distinguish clearly the difference of the dead and live spermatozoa with the eosin B staining. The morphological and structural characters of spermatozoa dyed by eosin B were studied in detail with light microscopy. The sperm has a top-like shape, and consists of an acrosome, nuclear cup and 5-10 radial arms which extend from the nucleus. The live spermatozoa were colorless, while the acrosome and nuclear cup of dead spermatozoa were stained easily by eosin B, and the boundaries of dead spermatozoa were not clear. The best concentration of eosin B and staining time were 2% and 2 min respectively. The acrosome reaction of spermatozoa were induced artificially by treatment with divalent cation ionophore A23187. And (92.73 ± 2.43)% of the emendatory rate of acrosome reaction was achieved when sperms isolated from the seminal receptacles of the female crab were exposed to 30 μg·mL^-1 ionophore A23187 for 50 min. There were significant positive correlation among the pratical value of eosin B staining、the pratical value of artificial induction of acrosome reaction and the theoretical value (P<0.01). It is concluded that both the method of eosin B staining and the method of artificial induction of acrosome reaction by ionophore A23187 were suitable for the viability assessment of spermatozoa in P. trituberculatus, and the results of these two methods were comparable.

Abstract:In recent years，an epidemic disease with the symptoms of darken appearance，erratic or disorientated swimming behavior，exophthalmia or opaqueness to eyes，inflammation or ulceration of the abdominal skin，and accumulation ascetic fluid in intestines and stomach，etc． was outbroken in cultured tilapia in Fujian，Guangdong and Hainan provinces．One strain of bacteria TL60829NA was isolated from the liver of diseased tilapia，the challenged tilapia presented the similar external signs such as exophthalmia and disorientated swimming behavior to those of the natural infected tilapia，so the isolate was the primary pathogenic agent of the epidemic disease in cultured tilapia．In conventional and Bio Merieux Vitek system tests, isolates were catalase negabive, β-haemolytic, Gram-positive cocci and serogroup B. By 16S rDNA amplified and sequenced，the phylogenetic tree of Streptococcicosis showed that the isolate clustered together with Streptococcus agalaciate， the S．iniae strains clustered together，the isolate was identified as S．agalaciate．The isolates were highly sensitive to 28 antibiotics such as ampicillin，kanamycin and penicillin G，and resistant to 15 antibiotics，such as tobracin, cotrimoxazole and ciprofloxacin．Histopathological analysis reveled that the gill's structure was broke down，the epithelial cells swelling；the membrane of the heart ruptured，the cardiac muscle hyperemia，disorderly arranged and leucocytes soaked；the essence structure of liver was destroyed obviously，pellet and fat denaturation；epithelia cells broke away from the intestines；the spleen was hemorrhage，dropsy and cellulose，a large amount of blood source pigmentation dyed pale brown by HE；essential structure of kidney was destroyed，obviously hyperemia and hemorrhage；the choroid and the orbital membrane inflamed and damaged，the crystalline lens fiber broken．

Abstract:In recent yaars, an epidemic disease with the symptoms of darken appearance, erratic or disorientated swimming behavior, exophthalmia or opaqueness to eyes, inflammation or ulceration of the abdominal skin, and accumulation ascetic fluid in intestines and stomach, etc. outbroken in cultured tilapia in Fujian, Guangdong and Hainan provinces. One strain of bacteria TL60829NA was isolated from the liver of diseased tilapia, the challenged tilapia presented the similar external signs such as exophthalmia and disorientated swimming behavior to those of the natural in fected tilapia, so the isolate was the primary pathogenic agent of the epidemic disease in cultured tilapia. In conventional and Bio Merieux Vitek system tests, isolates were catalase negative, β-haemolytic, Gram-positive cocci and serogroup B. By 16S rDNA amplified and sequenced, the phylogenetic tree of Streptococcicosis showed that the isolate clustered together with Streptococcus agalaciate, the S. iniae strains clustered together, the isolate was identified as S. agalaciate. The isolates were highly sensitive to 28 antibiotics such as ampicillin, kanamycin and penicillin G, and resistant to 15 antibiotics, such as tobracin, cotrimoxazole and ciprofloxacin. Histopathological analysis reveled that the gill's structure was broke down, the epithelial cells swelling; the membrane of the heart ruptured, the cardiac muscle hyperemia, disorderly arranged and leucocytes soaked; the essence structure of liver was destroyed obviously, pellet and fat denaturation; epithelia cells broke away from the intestines; the spleen was hemorrhage, dropsy and cellulose, a large amount of blood source pigmentation dyed pale brown by HE; essential structure of kidney was destroyed, obviously hyperemia and hemorrhage; the choroid and the orbital membrane inflamed and damagee, the crystalline lens fiber broken.

Abstract:This study examines the effects of sample size on various genetic structure parameters. The population genetic structure of cultured mirror carp (Cyprinus carpio) was estimated using microsatellite markers. 8 different sample sizes and 5 marker numbers were set up to analyze most genetic parameters including population alleles distribution, allele numbers(A), effect allele numbers(Ae), observed heterozygosity(Ho), expected heterozygosity(He) and polymorphism information content(PIC). As a results, population allele numbers rise dramatically along with sample sizes from 10 to 40 and then held a steady increase trends. Meanwhile 46.15% of loci showed high frequency allele. The results indicate that cultured population show predominant alleles in most loci because of selection pressure. Due to many homozygosity, the change of effect allele numbers, expected heterozygosity and polymorphism information content are little when the sample size is more than 40. In addition, the number of microsatellite markers and polymorhphism level also have a little effect on the estimation of population genetic structure. So, we suggested that the numbers of markers is more than 20 and sample size is 40 to 50 when using microsatellite markers to estimate population genetic structure.

Abstract:In order to understand the occurring and developing regularity and the essence of the Pseudodactylogrus bini disease in European eel (Anguilla anguilla）researches of the symptom, epizootic and gill histopathology of diseased European eel were made. The main symptoms of the diseased eel were abnormal swimming, unusual respiration, gill edema and mucus increasing. Although Pseudodactylogrus bini disease of European eel also occurred in winter, it mainly occurred in the end of spring, summer and the beginning of autumn when water temperature was above 26°C. There were five types in histopathological changes of gill. The first change was hyperplasia of epithelial calls in secondary gill lamellae which caused the fusion with the adjacent secondary gill lamella; The second was hyperplasia of mucous cells in secondary gill lamellae which also caused the fusion with the adjacent secondary gill lamella; The third was that secondary gill lamellae were edema but epithelial calls in secondary gill lamellae were not edema and detached from capillaries. The structure of the secondary gill lamellae disappeared as the epithelial cells were necrotic and lysis at the late stage; The fourth was that both secondary gill lamellae and epithelial cells were edema, and the layer of epithelial cells detached from capillaries. The structure of the secondary gill lamellae disappeared due to the necrosis of epithelial cells; The last one was formation of gill lamellae aneurisms which were club-shaped and global due to the dilatation and congestion of capillaries. All above five types in histopathological changes of gill influenced the respiratory function of diseased European eels, which reduced their growth or resulted in their death when the disease was severe.

Abstract:Pyrosequencing is a new DNA sequencing method, it was used to analyze single nucleotide polymorphisms recently years. Cathepsin-L gene is a lysosomal protease gene that is involved in the intermolt cycle of shrimp. In this study, genotyping of cathepsin-L gene (GenBank accession no. AY366355) SNP (C681G) in 96 Litopenaeus vannamei shrimps was performed using Pyrosequencing. The C/C,C/G and G/G genotype were found in this population, and the frequency were 0.81, 0.16 and 0.03, respectively. The frequency distribution was consistent with the law of Hardy-Weinberg. The statistic analyses showed that C681G SNP had no significantly association BW in this population (P>0.05)．The results of this study showed that pyrosequencing is a versatile technique that could improve the efficiency of SNP analysis for shrimp genomic research.

Abstract:Selecting small molecular ligands or monoclonal antibodies to cellular receptors as inhibitors is an effective approach to inhibit virus infection. In this research, haemocyte plasma membranes (HPM) of Chinese shrimp (Fenneropenaeus chinensis) were isolated employing differential centrifugation. Utilizing the techniques of Dot-Blot and ELISA, HPMs immobilized in microtiter plats or nitrocellulose (NC) membranes were incubated with Digoxingenin labeled white spot syndrome virus (WSSV-DIG) at 4℃ for 4 h. Then alkaline phosphatase labeled antibodies against DIG was used as a sensitive probe to detect the in vitro combination of WSSV-DIG to HPM. Both ELISA and Dot-Blot combination showed positive reactions. In blocking experiment, polyclonal antibody against haemocytes of Chinese shrimp was allowed to bind to the HPM at 37℃ for 1 h before the incubation with WSSV-DIG. In Dot-Blot assay, the blocked group showed a significantly lighter color compared with the unblocked group. In ELISA assay, OD value of the blocked group was 69% lower than the unblocked group. It can be deduced that some receptor antibodies, which were specifically against the WSSV receptors, existed in the polyclonal antibody. During incubation, these antibodies adhered to the receptors on the HPM and significantly blocked the combination of WSSV-DIG. The in vitro combining technology between WSSV and HPM developed in this research provide a strategy to characterization of WSSV receptors and selection inhibitor to WSSV. The blocking experiments carried out with polyclonal antibody have proved the feasibility.

Abstract:The arginine kinase was purified from muscle tissue of the shrimp, Littopenaeus vannamei. The crude extract was treated with CM-cellulose in a batch procedure. Fractionation of arginine kinase was performed by SephadexG-100 chromatography and followed by DEAE-cellulose 32 ion-exchange chromatography. The molecular weight of it was about 40 ku, as judged by SDS-polyacrylamide-gel electrophoresis. The enzyme remained stable at 25-55℃ within 60 min and inactivated at higher temperature (65℃). The activity of purified shrimp arginine kinase was remained stable in the range of pH 6.0-8.0. Treated with 10 mmol·L^-1 arginine, NaCl, KCl, MgCl₂, the enzyme activity significantly increased. However, the enzyme activity was obviously inhibited by its substrate analogs such as spermine, amino guanidine, CuCl₂, MnCl₂.

Abstract:Eutrophication caused by mariculture has become a serious environmental problem. Seaweeds would play an important role for decreasing marine eutrophication due to the cost saving, low sensitivity to environmental and impurity factors, the possible contaminant recovery from the biomaterial and its elevated adsorption capacity. Seaweeds are able to absorb large quantities of nitrogen, phosphorus and carbon dioxide, produce large quantities of oxygen, and have excellent effect on decreasing eutrophication. In this paper, ammonium nitrogen removing efficiency and absorption rate by Gracilaria asiatica with different culture densities were determined, and dynamics character of ammonium nitrogen uptaking at N-limited and the N-replete situation and the effect of different initial concentration of ammonium nitrogen on absorption rate were studied. Gracilaria asiatica was collected at Xiangshan harbor, Zhejiang province, southern China, and cultivated in the laboratory. Samples of the alga were maintained in a flask with 250 mL seawater of 21 salinity. The alga were cultured in culture boxes at (20±1) ℃, under 60 μmol·m^-2·s^-1 illumination, and on 12 h:12 h light/dark cycle. The result showed that the ability of ammonium nitrogen removing was enhanced by seaweed culture density (in 2-24 g·L^-1) and experiment time (in 5 hours) increasing. The highest efficiency of ammonium nitrogen removing with highest density (24 g·L^-1) of G. asiatica was up to 99.77% after 5 hours. Ammonium nitrogen concentration declined from 300 μmol·L^-1 to zero. The ammonium nitrogen removing efficiency with lowest density (2 g·L^-1) was only 20%. Higher ammonium nitrogen absorption rate (30-41 μmol·g^-1·h^-1) was kept in different density groups during initial culture period, especially in 16 g·L^-1 density group, then decreased with density increase. The maximum uptake rates reached as high as 28.33 μmol·g^-1h^-1and 18.85 μmol·g^-1·h^-1 at 3 h and 5 h, respectively, in 2 g·L^-1 minimum density group. The lowest ammonium nitrogen uptake rate of 11.70 μmol·g^-1·h^-1 and 1.90 μmol·g^-1·h^-1 were obtained at 3 h and 5 h with the highest density group (24g/L). In initial concentration experiment, maximum uptake rates (V_max) and half-saturation constant(Km) of G. asiatica at N-limited and the N-replete situation reached the highest value, 116.47, 159.40 μmol·g^-1·h^-1 and 439.70, 913.61 μmol·L^-1 in the first hour, then they declined from 24.29, 23.22 μmol·g^-1h^{-1 and 166.87, 255.30 μmol·L-1 with culture prolonging from 1 h to 5 h. In initial concentration experiment, ammonium nitrogen removing efficiency were increased with initial concentration reduced in the range of 100-300 μmol·L-1, especially with lowest ammonium nitrogen concentration (100 μmol·L-1). Ammonium nitrogen removing efficiency kept in 56.7%-67.4% with 300-500 μmol·L-1 of ammonium nitrogen concentration. There was no difference for ammonium nitrogen absorption of G. asiatica at between N-limited and the N-replete situation. Within 300-500 μmol·L-1 of ammonium nitrogen concentration, a fast absorption rate of G. asiatica at N-half hungry situation presented in the first stage(40.7-102.1 μmol·g-1·h-1), and almost had a positive relation with concentration, which was not fit the Micheal dynamics saturation equations. But, within 100-200 μmol·L-1 of ammonium nitrogen concentration, the uptake rates of G. asiatica were as low as 17.8-40.8 μmol·g-1·h-1. When the concentration decreased in some limited range, the absorption rate reached the maximum and fit the Micheal dynamics saturation equations. It would provide important theory data for cleaning water and bioremediation by cultivating G. asiatica, and large-scale cultivation of G. asiatica could be a good solution to the problem of eutrophication due to their capability of removing nutrients.}

Abstract:Scortum barcoo was an excellent economical fresh water fish which was native in Australia and introduced into China in 2001. After several years domesticated, it can be reproduced and have been an aquaculture target in China, but the fry produce efficiency was very low. In order to make knowledge of growth and development of larva, juveniles of Scortum barcoo and offer basic data for large-scale fry produce, it was studied in this paper by observation, description, and photograph on growth and development. Larva body length of the newly hatching larva ranged from 2.32 mm to 2.98 mm in total length when the water temperature was about 26.6-29.7 ℃. The volume of the larva’s yolk sac and oil globule was (0.74±0.15) mm³ (n=20) and (0.07±0.17) mm³ (n=20) respectively. Coloration of eyes by pigment and 4 pair of branches appeared on 1-day-old. Larva mouth shut up, gut started peristalsis, and swim bladder occurred on 2-day-old. Larva started feeding on 3-day-old. Hereafter, the ontogeny embarked on the post-larval stages. The ontogeny larva was on the juvenile stages after 20 days, larva fin ray completely developed, and scales occurred. Lateral line scale occurred on 23-day-old. Scales entirely developed on 28-day-old, and the ontogeny embarked on the fingerling stages. The relationship between total body length (TL) and age in days (D) was described as: TL=-0.0003D³+0.0339D²+0.1992D+3.4288（R²=0.9913）. The relationships between body length (L) and body weight (W) of larva and juveniles of Scortum barcoo was described as: W=0.0001L^2.5059（R²=0.9976）. The relationship between body length and body height during development of Scortum barcoo larva, juveniles was significant and the formula was described as: L=0.0005H³-0.0353H²+1.0125H-4.620(R²=0.993)。All these data would be benefit with practice of Scortum barcoo fry production.