Abstract:Megalobrama pellegrini, a cyprinid fish belonging to Cultrinae, lives only in the upper reaches of the Yangtze River, mainly in Sichuan Province. Due to the loss of habitat after the completion of the Three Gorges Project and overfishing, it was forecasted that the population sizes of M. pellegrini might decrease sharply in the future. Surveys on its biology, reproductive ecology, artificial propagation, and ontogenesis have been done since 2001 to seek suitable countermeasures for conservation and resource-recovery of this endemic species. The present paper reports the results of observation on postembryonic development of M. pellegrini. Six batches of larva obtained by artificial fertilization and incubation were used in this study, and the ontogenesis process was observed repeatedly. Postembryonic development of M. pellegrini could be divided into two periods, namely larva and juvenile, including 16 stages. The newly-hatched larva was transparent, lying at the bottom quietly, with 43 pairs of muscle nodes and a mean of （4.78 ? 1.12） mm in total length. One-chamber air bladder occurred at 89.5 h after hatching, and the larvae began to feed. Larva older than 115.5 hours depended on exterior nutrition completely since yolk was exhausted. As the larva grew, pectoral fin, dorsal fin, caudal fin, anal fin, and ventral fin developed in sequence. Scales appeared in larvae of （ 19.75?3.71 ）mm in total length, when they were 47 days old. This declared the beginning of juvenile period. While the water temperature varied from 22. 2 to 25. 0 degrees centigrade, postembryonic development of M. pelleghrd, ending at the formation of scales, lasted for 68 days, when the young was （ 31.82 ? 3.87） mm in total length. Growth in length and body morphometrics varied during different developmental stages. The maximal growth rate appeared in hatching stage, and it seemed slower incoordinately in later stages. The proportion of post-anal length to total length increased gradually from 20.92% at the beginning, and it stabilized at about 45% finally. However, the ratio of body height to body length decreased, becoming nearer and nearer to the scale of adult in the young fish period. The ontogeny process of M. pellegrini was similar to that of other Cyprinidae fish, nevertheless some details in development such as the size of newly-hatched larva, the growth rate, and the size of air-bladders could be used to distinguish M. pellegrini from other Megalobrama species. Suggestion on the conservation and utilization of M. pellegrini species was discussed at the end of this paper.

Abstract:The phyllosoma larvae（ Ⅰ - Ⅳ ） of Patudirus stimpsoni of early development were collected from marine farm of Fisheries College of Jimei University from July to Sep. from 2000 to 2001. The histology, histochemistry and ultrastructure of their hepatopancreas were studied with light and electron microscopes. The results show that the hepatopancreas are made of two parets （right and left） and each part can be divided into three lobes that consist of many hepatopancreatic tubules, which increases in length and amount with the development of larva. Hepatopancreas connects the pyloric stomach and the midgut with two common gland duct （right and left）. The epithelium cells of hepatopancreatic tubules are classified into blister-like cells （B-cells）, resorptive cells （R- cells）, fibrillar cells（F-cells） and embryonic cells（E-cells） based on structure and function. The surface of all type cells has microvilli and these cells are located on a thin basement membrane. B-cells are mainly located in the proximal regions of the tubules, their volumes are the biggest and shapes are not regular, nuclei are crescent. B-cells have a large digestive vacuole, the denes cytoplasm, pinocytofic vesicles, small mitochondda exist in an apical complex body between the microvilli and large digestive vacuole. There are rough endoplasmic reticulum（RER） in basement of the cells. R-cells are the most numerous cell type, their nuclei are near round and located in the basement of cells. In some R-cells（ called Rl-cell）,no vacuoles are observed while some R-cells（ called R2-cell）have many vacuoles（under light microscope）. Mitochondria with moderate electron density matrix are developed and have many ridges, and RER and free ribosome are rich in Rl-cells where plnocytotic vesicles and dense granules were rarely observed. But in R2-cells, electron density of mitochondria is low and ridges are a few, there is the extensive and well-developed smooth endoplasmic reticulum （SER） containing material of high density in the basal region of the cell, some vesicles appeared around Golgi bodies and lipid droplets are a few or are forming in R2-cells. F-cells are mainly located in the middle regions of the tubules and scattering among B-cells and R-cells. It is strongly basophile, their nuclei are large and located in the middle regions of cells. RER, mitochondria and ribosome are very rich and zymogen granules aggregated in the apical cytoplasm. E-cells are located in the blind end of the tubules and undifferentiated, their volumes are small and a round or oval nucleus exists in middle regions of cells, and show a high ratio of nucleus to cytoplasm, cytoplasmic organelles are undeveloped in the E-cells. The study of histochemistry showed that four types of hepatopancreatic cells contained generality polysaccharides; there are some glycogen and lipid droplets in R-cells; the proteinic content is rich in the F-cells but less in other type of cells. The relation between the structure and function of four types of hepatopancreatic cells of the phyllosoma larvae was studied too in this paper. It is generally believed that the main absorptive and digestive function of the gland is carried out by the B-cells which ingest nutrients by pinocytosis and process them in a large digestive vacuole;the R-cells absorb soluble material from the lumen by diffusion and store them as lipid and glycogen in the cytoplasm;F-cells synthesize zymogen granules which are exocytosed into the tubule lumen and carry out function of extracellular digestion. E-cells divide by mitosis to differentiate into other tvoe of cells.

Abstract:The researches on conservation of conchocelies germplasm of Porphyra hahanensis were done. Three different kinds of conservation methods （Liquid conservation, solid conservation and encapsulation cryopreservation） were compared. The result showed： 1） The weights of conchocelies germplasm increased by - 0.67% during the 30 days under the condition of temperature 5℃ and they could develop normally up to 120 days without changing culture medium under the temperature 10℃ when the method of liquid conservation was used. 2） The conchocelies germplasm did not adapte to low temperature 5℃ condition in despite of the bacterium growing slowly and rarely and the conchocelies grew normally for 100 days when the method of solid conservation was used. 3） The 75% of survival rate of the conchocelies germplasm was kept when the method of encapsulation cryopreservation was used.

Abstract:The changes in isozyme patterns during early ontogeny （from unfertilized eggs to the 1st stage of young crab） of Ponunus trituberculatus were investigated. Eleven isozymes （ LDH, GDH, ADH, SOD, EST, ME, MDH, SDH, GOT, ACP and α-AMY ） were analyzed by vertical slab polyacrylamide gel electrophoresis. The results showed that the electrophoretograms of seven isozymes （ EST,ME,MDH,SDH, GOT, ACP and α-AMY ） exhibited obvious differences among early ontogenic stages of P. trituberculatus, and the complexity of electrophoretogram pattern tended to increase with development in most of the seven isozymic systems. The stage-specific isozymes can be used as the biochemical indices to identify the specificity of a certain developmental stage. No activity of LDH and GDH was detected during early ontogeny of P. trituberculatths （in the present paper）, Both ADH and SOD isozymes had stable expression at every developmental stage of P. trituberculatus, ADH isozyme had one band, and SOD isozyme had two bands. According to the ontogenetic patterns of eleven isozymes, the expression of isozymes during ontogeny of P. trituberculatus was divided into four types. The ontogenetic polymorphism of isozyme and the isozyme activity at the 1st zoeal stage newly after hatching were also discussed in the present paper.

Abstract:The Cyprinus carpio （6 months old） were exposed to water bodies with different concentration of Cr^6＋ ranged from 0,0.12, 0.67,1.22, 3.66, 10.97 and 32.91 mg?L^-1, respectively. An increase in growth rote （AGR and ALR） was observed in T0.12 to T3.66 Cr^6＋ -treated groups. The results showed that Cr^6＋ also affected serum osmolarity and serum electrolytes. The serum osmolality and Na^＋ and Ca^2＋ concentration were significantly higher in the Cr^6＋ - treared groups than in the controls. Increase of serum K^＋ was also observed, but it was only significant in T10.97 group. The concentrations of serum Mg^2＋ from a few Cr^6＋ treated groups were decreased. No obvious serum Cl^- concentration changes were observed. Cr^6＋ affected serum hormonal responses. The T3 content in T3.66 group and T4 content in T10.93 group, and the cortisol levels from all the groups treated with Cr^6＋ concentration 0.67 and higher were significantly increased. The nutritional contents （crude protein and crude fat） in fish from most of the Cr^6＋ treated groups were lower than the control. The concentration of Cr in a fish body treated with Cr^6＋ had a distribution pattern： muscle 〈 gill 〈 liver 〈 Intestines. The Cr concentration in fish muscle from group T32 91 （3.00 mg?kg^-1） and the Cr concentration in intestines from group T0.67（2.24 mg?kg^-1 ） and from all the groups treated with higher Cr^6＋ exceeded the national maximum limit for food safety.

Abstract:Based on the data from four seasonal oceanographic censuses in the East China Sea （23?30′ - 33?N, 118?30′ - 128?E） in 1997 - 2000, this paper discussed the ecological characters of the dominant species of Decapods in the East China Sea and significance in the form of fishing ground. Results showed that there were four dominant species of Decapods, Lucifer intermedius, Leptochela gracilis, lucifer penicillifer and leacifer hanseni, leacifer intermedius and leacifer penicillifer were warm-water species offshore, lucifer peniclllifer was warm-water sea species. Leptochela gracilis was eurythermic halobiotic species. The warm-water species offshore exhibited not only higher abundances but also bigger average dominance and abundance percentages of dominant species in total abundance than other species. The eurythermic halobiotic species usually exhibited higher occurrence frequency. For example, Leptocheia gracilis occurred in every district and season in the East China Sea though its abundance was relatively lower. Analysis in aggregation intensity of dominant species showed that the warm species with poor ability of adaptation to low temperature showed higher aggregation in summer. That was why the aggregation intensity of Lucifer peniciUifer and Lucifer hanseni was higher than that of Lucifer intermedius in that season. Different from other zooplankton in the East China Sea, the dominant species of Decapods showed such ecological characters as highest abundant level in summer, individuals of stenohaline species in most, distribution in costal and estuary near the fish spawn ground, which were very important in the fishery.

Abstract:Oxyeleotris marmoratus is a member of the family Eleotridae, native to the southeastem Asia, such as Thailand, Vietnam and Cambodia. It is one of important economic fish in those countries. It is one of the largest in body size in family Eleotridae, and the biggest individual weights above 5 kg. In 1980s the fish was introduced to China, but the culture industry of this fish did not estabhsh, because the artificial propagation of this fish did not succeed. In 1999, some Oxyeleotris marmoratus fingerlings in size 4 cm were introduced to China for domestication and culture from Viemam. When reared in pond for one year, some individuals have been matured. With the experimentation of artificial propagation for several years, some data of propagation and embryonic development of Oxyeleotris mannoratus have been obtained. The fish propagation period in one year is from March to November in original country, and is from May to September in Guangzhou of China. In this paper, the complete artificial propagation and embryonic development of Oxyeleotris mannoratus have been studied. When reared for one year in pond in Guangzhou, some of the fish become mature. Behaviours of propagation of the fish in nature could be conlrolled by adjusting the ecologic condition of environment they lived in and the spawning rate was 65.6 %. By injection of hormone into it, we also could make the fish spawn and the spawning rate was 72.7 % - 100%. 1.54 million eggs were obtained and 85.1% - 90.3% among these were fertilized eggs. The fertilization eggs are clarity and like melon or pear in shape. The egg＇ s length is from 1.3 mm to 2.4 mm and its width is from 0.56 mm to 0.7 mm. There are several ten fat balls in its yolk vesicle and the yolk is at the end of egg. There is an adhesion tray made of adhesion silk on the thin end of fertilized egg. The length of adhere silk is from 0.20 mm to 0.23 mm, the width of adhesion tray is from 0.15 mm to 0.17 mm. When water temperature was 26.8℃ - 30℃, egg plasm, 32 minutes after fertilization, undergoes the first cleavage. 30 hours and 25 minutes after fertilization, some embryos begin to break the membrane and come out and hatching＇ s length is from 2.9 mm to 3.1 mm. The hatch rates were from 76% to 85.6%. 4 days after hatching, the fry can swim fiat and its heartbeat is from 120 to 150 in one minute, its length is from 3.5 mm to 3.9 mm, its muscle section is 7 - 10 ＋ 14 - 17. Its egg yolk is absorbed completely and it can be fed with artificial food then. The artificial propagation of Oxyeleotris marmoratus was fulfilled first in China.

Abstract:The embryonic development of the sea slugOnchidium sp. was observed and described at 3 temperature groups and the main factors affecting the veliger larva released were also examined in artificial conditions. Results showed： The embryonic development process of sea slug was similar to that of other Pulmonate species. The newly laid eggs were fertilized eggs with no division. They then entered into 7 stages such as the cleavage, blastula, gastrula, intracapsular trochophore, veliger in capsule, hatching or release, and the free-swimming veliger, At water temperatures of 26℃, 28℃ and 30℃, it took 300, 290, 288 hours respectively, of development from the zygote to the free-swimming veliger for the sea slug, The body sizes, shapes, interior structures and the metamorphosis of every period of larvae were also recorded under microscopic observation, It is found that the main factors that affected the release were water temperature and the stimulation of sea water, The ceasing of embryo development was first reported at the temperature of below 23℃.

Abstract:Morphological characteristics of the parthenogentic egg of Daphnia （ Ctenodaphnia ） carinata during the embryonic development were studied. At 26℃, the embryonic development took 31 h, including 11 h for the egg stage, 8 h for the long embryo stage, 9 h for the double compound eyes stage and 3 h for the single compound eye stage. Each stage was divided into several sub-stages according to the characteristics during the embryonic development. Therefore, the embryonic development could be divided into eight stages, each of which would be described in detail. At the egg stage, the egg was just spawned from the female＇s ovary, then began to grow up quickly and its inner appearance changed gradually from translucent to transparent, Seven hours later distinct vitelline granules occurred in the egg. At the long embryo stage, the embryo became elongated anteroposteriorly, The egg membrane was cast off. The vitelline granules extended into the cephalic region and all rudiments formed. At the double compound eyes stage, the embryo further elongated with a distinct head, Two pink patches and a brown dot were observed in the head which represented the paired eyes and the oceellus, respectively. The limb rudiments could be seen on the ventral margin of the embryo. At the single compound eye stage, the embryo reached maximum elongation with the eyes becoming dark in color and paired eyes finally fused. The development of the alimentary canal was complete. Trunk appendages became distinct. The juveniles then emerged from the brood pouch. The composition and content of proteins and amino acids during the embryonic development were also measured and analyzed. The results showed the content of soluble proteins decreased during the embryonic development even though it slightly increased at the long embryo stage. The composition of soluble protein changed from the big molecular weight to small molecular weight. Seventeen amino acids during the embryonic development were measured, including 7 essential acids, 8 non-essential acids and 2 semi-essential acids. The content of amino acids decreased during the embryonic development, but slightly increased at the long embryo stage. The Glu content was the highest of all amino acids and the Leu content was the highest of 7 essential acids. The content of proteins and amino acids decreased at the egg stage, but increased at the long embryo stage, then decreased gradually at the double compound eyes stage and single compound eye stage. This changing pattern of the content of proteins and amino acids correlated well with the morphological characteristics during the embryonic development. Based on the morphological characteristics and content and cunaposition of proteins and amino acids during the embryonic development in Daphnia （ Ctenodaphnia ） carinata, it is concluded that the proteins and amino acids were the main nourishment materials during the embryonic development, which not only were used to build the embryonic tissues and organs, but also provided the energy for developing embryo.

Abstract:Fed with feeds containing seven levels of Spirulinaplatensis （0, 0.2%, 0.5%, 0.8%, 1.5%, 3%, 5%） for 8 weeks respectively, the grouped Litopertaeus vannamei were weighed and counted on the 28th and on the 56th day. And the body composition （crude protein, amino acid, fatty acid, etc. ） and hepatopancreas somatic index （HSI） were investigated at the end of the experiment. When the dietary level of Spirulina platensis was 0.8% and 1.5%, the shrimps had more rapid weight gain （WG） with the 28th WG 926.10% ,959.78% respectively and the 56th 4382% ,4353.3%. And when the dietary level of Spirulina platensis was 0.8%, the feed conversion ratio （PCR） was 1.32, the lowest; and protein efficiency ratio（PER） was 1.296, the highest. The EPA content of the shrimp body（Y） had good linear relationship with the S. platensis supplementing level（X） within the 1% addition level （ YEPA = 2. 4275X ＋ 4. 5975, R^2 = 0. 9611 ）, at the same time, the DHA and ARA content had remarkable linear relationship with the S. platensis within the level of 0.8% （ YDHA = 4. 668X ＋ 5. 6545, R^2 = 0. 9631 ; YARA = 105.58X ＋ 0. 3241, R2 = 0. 9749）. The HSI of the shrimp had the decrease tendency along with the increase of the dietary level of S. platensis. These results showed that the S. platensis had some beneficial grow performance and the digestive/absorbent rate, especially when the addition level was 0.8 %. The S. platensis had remarkable effect on the deposition of high unsaturated fatty acids（HUFAs）. According to the equation of dietary level of S. platensis and HUFAs, when the level was 3.67 %, the total contents of HUFAs of shrimps peaked.

Abstract:Two 8-week feeding trials were conducted to investigate effects of different rapeseed meal levels（0.0 - 50.0% ） on growth, feed utilization, blood biochemical indices and toxins residues in grass carp（ Ctenoparyngodon ideUus ） （ average body weight were about 5.0 g and 18.7 g）. The results showed that： with the increasing of the rapeseed meal levels, the weight gain rate, specific growth rate,feed efficiency ratio and protein efficiency ratio decreased, but no significant difference was observed in 0.0, 10.0% ,20.0% and 30.0% groups. Glucosinolate（ GLS ）, isothiocyanate （ITC） and oxazolidine thione（OZT） content in the muscle and liver also increased with the rapeseed meal level increasing in average body weight 5.0 g; In average body weight 18.7 g, there were no significant difference in serum glutamic-oxalacetic transaminase, glutamic-pyruvic transaminase, glutamic-oxalacetic transaminase/ glutamic-pyruvic transaminase, total protein, albumin, globin, albumin/globin, urea nitrogen, glucose, creatinine, T3 and T3/T4 , but T4 and T3 ＋ T4 levels were significantly lower than those of control, liver cells were damaged. From the two trials , a percentage of no more than 30.0 % of rapeseed meal supplementation in the feed was suitable.

Abstract:Based on the fact that medium - chain triglyceddes suppress accumulation of reserved lipids in mammals and some fish species, the effect of dietary laurate on lipid accumulation and vitality was further examined in red sea bream. Ethyl laurate （0.5 % ） supplemented to the diet was fed to zero - year red sea bream （0.3 g） for 47 days. While dietary laurate did not influence growth performance, increasing of muscle ratio and decreasing of liver weight were observed. The dietary laurate led to reducing liver triglycerides, intraperitoneal fat body ratio, adipocyte diameter, and liver lipid. In addition, docosahexaenoic acid （DHA）, functioning as a physiologically active nutrient, tended to increase in the muscle, liver, heart, brain and eyes. Dietary laurate activated resistance against air-dipping and liver function, as seen in the case of dietary DHA fortification. It is concluded that dietary laurate could depress lipid accumulation and improve vitality, while the influence of laurate on the tissue DHA deposition might relate to its efficacy.

Abstract:Outbreak of cyanobacteria blooms, with associated unsightly scum and unpleasant odor, occurs regularly in the eutrophication lakes. Using filter-feeding fish is one of the ways to control the blooms. Based on the studies on ingestion and digestion of cyanobacteda Microcystis aeruginosa by tilapia under laboratory conditions, we carded out field testing to use tilapia to control cyanobacteria blooms in Lake Yuehu and other eutrophication lakes in Ningbo, China from 2000 to 2003. The results show that the tilapia were capable of ingesting and digesting large quantity of cyanobacteria. The average digestion rate of Microcystis aeruginosa by fingerling tilapia ranged from 58.6% to 78. 1% at the water temperature of 25℃, and the ingestion rate increased with increasing fish weight and water temperature. Outbreak of cyanobacteria blooms occurred in Lake Yuehu in both 1999 and 2000. The lake was stocked with cultured silver carp, bighead carp and mussel （9.8 g?m^-3） at the beginning of 2001 and cultured tilapia （3 - 5 g?m^-3） in April of 2002. Cyanobacteria bloom has not occurred ever since. From June to October, the average total phytoplankton density decreased from 897.6?10^6 cells? L^-1 in 2000 to 291.7?10^6 cells?L^-1 in 2001 and 183.0?10^6 cells?L^-1 in 2002. The annual average phytoplankton biomass in 2001 and 2002 decreased 48.6 % and 63.8 %, respectively, from that of 2000. The cyanobacterla as proportion of phytoplankton biomass decreased from 70% in 2000 to 22.1% in 2001 and 11.2% in 2002. In the meantime, the water transparency （Secci disk depth） increased from 20 - 50 cm to 55 - 137 cm. Similar results were obtained in some other eutrophication water bodies. For example, at the lake in Zhenghai park, algal bloom disappeared about 20 days after tilapia fingerlings were stocked （8- 15 g?m-3）. The chlorophyll a concentration and phytoplankton productivity declined dramatically whereas the water transparency increased substantially. How the stocked tilapia affects the nutrient （e. g. nitrogen and phosphorus） dynamics in the natural lakes needs further studies. Stocking tilapia is an effective measure to control cyanobacteria blooms in eutrophication water bodies, especially in lakes where the nutrient inputs cannot be reduced sufficiently, and where zooplankton cannot effectively control phytoplankton production.

Abstract:The relationship between sample size and the accuracy in the assays on immune activity of population of Fenneropenaeus chinensis was studied. The superoxide dismutase （SOD） activity, lysozyme （LSZ） activity and the total haemocyte counts （THCs） of the juvenile shrimp were detected with xanthine-oxidation method, advanced Hultmark method, and haemocytometer method, respectively. The mean coefficient of variation of the three assays were ? 2.34%, ?4.67% and ? 4.58% respectively. When a predefined confidence zone of the sample＇s observation located in the range of acceptable error, the observation on samples reflected the real state of the population. When the mean coefficient of variation of the assays was regarded as the acceptable errors of the detections, and a 95% confidence level of the observation was adopted, the sample sizes of 80, 70 and 120 were needed for the accurate reflection of the real SOD, LSZ and THCs of the population respectively. If a 90% confidence level of the observation was adopted, the sample sizes for the reflection of real SOD, LSZ and THCs of the shrimp population were as large as 50, 50, 80 resoectively.

Abstract:Seven strains were isolated from Pseudosciaena crocea suffering from the skin-ulcer disease cultivated in Xiangshan Area of Zhejiang Province. Strain ZXS01 ,ZXS02 and ZXS07 were confirmed to be the pathogen of the disease by artificial infection test. The traditional physiological and biochemical methods showed that most of the phenotypes of strain ZXS02 were similar to Proteus. In order to investigate the phylogenetic position of this pathogen, 16S rRNA gene was sequenced, its molecular weight is 1495 bp. Molecular phylogenetic dendrogram was constructed based on the genetic distance analysis, which revealed that strain ZXS02 exhibited higher levels of 99.0% similarity to Proteus trdrabilis. Meanwhile, Sensitire （gram negative） identification system was applied in the determination of strain ZXS02, showing 99.96 % similarity with reference strain of P. mirabilis. Based on the results obtained from phenotypes and 16S rRNA gene analysis, strain ZXS02 was identified as P. mirabilis. Furthermore, its sensitivity to 23 antibiotics, temperature and salt were detected, the results showed that it was sensitive to chlommycetin and other 3 kinds of antibiotic, and the optimum temperature and salinity are 37℃ and 20 respectively.

Abstract:An epidemic disease named“muscle emulsification disease” consecutively happened in cultured swimming crab Portuns trituberculatus during the years 2003 - 2004 in Zhousan, Zhejiang Province. This disease, with the symptoms of muscle shrink and emulsification, mainly occurred on temporarily cultured swimming crab in low water temperature from Oct. to Feb., caused serious loss. A great deal of yeast-like organism was observed from the milky emulsion in the leg, and with lid open, milky liquid was seen. as well as in muscle,heart, hepatopancreas from the disease crab. These yeast-like organism were isolated and cultured with TCBS agar and identified as Candida oleophila. Artificial challenge test showed that the isolated yeast could cause emulsification disease of health swimming crab, when injected or dipped with the cultured yeast, with the similar symptom as the naturally infected crab. oleophila was re-isolated from the artificial infected crab. The results showed that Candida oleophila was the pathogen of the muscle emulsification disease of swimming crab in Zhejiang Province in recent years.

Abstract:In order to inquire into the effect of freeze on protein denaturation of shellfish food and improve the quality, take the Paphia undulata as an example, the effects of different freezing and frozen temperatures on salt-solubility and ATPase activity of myofibrillar protein in three kinds of the Paphia undulata＇s meat were studied in this paper. The results show that the final temperature of freezing have little effect on freeze denaturation of the Paphia undulata. However , the frozen stored temperature showed the freeze denaturation of protein evidently, the lower the frozen temperature, the less the extent of freeze denaturation; for three forms of the Paphia undulata, have more effect on the protein denaturation surimi and fragmentary meat as muscle structure destroyed than intact muscle tissue. It was also observed that the freezing denatureation of myofibrillar protein in shellfish meat could be efficiently reduced by addition of cryoprotectants especially in of surimi. Therefore application of addition cryoprotectants can effectively improve the quality of frozen shellfish.

Abstract:Complement is a humoral factor of innate immunity and plays important roles in immune surveillance and clearance of invading pathogens. This system is directly and immediately activated in an immune-competent host, and the altemative（ antibodyindependent）, Lectin （triggered by mannose-binding lectin） and classical pathways （antibody-dependent） have been described in fish. All three pathways converge to the lytic pathway, leading to opsonization or direct killing of the microorganism. The alternative and lectin pathways are ancient mechanisms present in invertebrates as well as ancient vertebrates. Some of the agents, like zymosan and LPS （lipopolysaccharide）, are known activators of the alternative pathway of fish complement. The lectin pathway, which has not been much studied in-teleosts, is activated by the binding of mannose on the surface of microorganisms to a complex of mannosebinding lectin （MBL） and MBL-associated serine protease （MASP）. Fish complements are comparable to those of mammals but some important differences have been described. Fish sertun shows hemolytic activity indistinguishable from that of mammalian compleraent. In general the complement system of the altemative pathway is more active in fish than in mammals, is not heat labile and therefore difficult to preserve. Fish complement has lower optimum reaction temperature than its mammalian counterpart, and its components, like C3. The complement system is composed of numerous proteins and all pathways generate factor C3, which has been described and isolated from teleost species. Complement C3 is a central molecule in the complement system whose activation is essential for all the important functions performed by this system. Complement proteins in fish, like C3 and B factor, are more polymorphic. Here we describe some characteristics of the complement system of fish.

Abstract:inbreeding, which refers to situations where relatives are mating, is unavoidable in aquaculture populations because of their restricted population size. The rote of inbreeding in a population is roughly equal to one over twice the ‘effective population size＇, 1/ （2Ne）, but a more accurate ‘inbreeding coefficient＇ （F） is usually used to quantify inbreeding in populations undergoing artificial and/or natural selection. Inbreeding usually leads to reductions of performance in aquaculture species. Such ‘inbreeding depression＇ is mainly the result of recessive deleterious genes being uumasked and expressed in homozygous individuals. All aquaculture populations will accumulate recessive deleterious genes because of mutations in the DNA. It is assumed that most aquaculture species have a‘genetic load＇ of about 100 recessive deleterious genes, which would be more than enough to cause the extinction of that species if these genes were made homozygous through mating between relatives. A literature review confirmed that traits related to the overall fitness of aquaculture species are strongly affected by inbreeding （ranging between 3% - 50% inbreeding depression per 10% increase of the inbreeding coefficient, F）. Fast inbreeding through full-sib mating has resulted, on average, in three times higher inbreeding depression in growth compared to slow inbreeding in large-scale selective breeding programs. Studies with other species suggest that slow inbreeding usually lead to more effective purging of recessive deleterious genes than rapid full-sib inbreeding since fewer genes are fixed because of random drift. Inbreeding will also reduce the additive genetic variation within hatchery populations, but increases the additive genetic variation between isolated hatchery populations. Inbred populations usually show different responses in different environments due to the reduced additive genetic variance and their loss of ability to adapt to environmental changes. Therefore, efforts should be made to restrict inbreeding and its negative consequences on the production efficiency of aquaculture species fanned in China. It is recommended that hatcheries, which are maintaining their own broodstock, should restrict inbreeding by securing an effective population size （ Ne ） of minimum 50 individuals. Crossbreeding schemes, which are masking the negative consequences of inbreeding in different hatchery populations, could be used to secure a long-term conservation of aquaculture species. However, only selective breeding has the potential to genetically improve aquaculture species compared to the best performing wild populations. No matter which selection strategy is used, i.e. mass-selection, family selection, within-family selection, combined family and within- family selection or marker-assisted selection （MAS）, accumulation of inbreeding should be restricted to about 1% per generation of selection. Such low inbreeding should be secured by producing full-sib families in separate rearing units, from which samples of individuals are tested and used as potential breeding candidates.

Abstract:The data reported in the update literature on the effects of vitamin C on the nutritional physiology and immunity of fish are compiled and discussed. The vitamin C requirements of fishes usually vary to some degrees by species, size, environmental factors and the chemical or physical status of vitamin C. Three evaluation indices（ growth, tissue concentration and immunity parmneters）are often used to estimate the vitamin C requiement of fish. The vitamin C requirements based on constant tissue concentration of vitamin C are generally higher than those on growth performance. Furthermore, vitamin C requirements based on immunity parameters are much higher than those on contant tissue concentration and growth performance. Usually, high level of dietary vitamin C can increase the resistance to stresses and diseases in fish although there are some study results showing no beneficial effect on the non-specific immunity of fish. The research fields in future are also presented in this review.

Abstract:The precociousness of Chinese mitten-handed crab （ Eriocheir sinensis ） is correlative with the level of estradiol in the hernolymph and gonad. In female, the hemolymph estradiol level of immature crab was （ 118.75 ? 11.25 ） pg. mL^-1, which was much lower than those of precocious and mature crab （ （ 291.84?33.71 ） pg?mL^-1 for the former and （ 261.01 ? 54.49 ） pg?mL^-1 for the latter） （ P 〈 0.01 ）. The estradiol levels in the hemolymph of female crab with precocious gonad was higher than those of female crab with mature gonad while ovarian estradiol level of female crab with precocious gonad was lower than the latter（ （232.16?32.40） pg?g^-1 for the precocious crab and （257.77 ? 39.40） pg?g^-1 for the mature crab）（ P 〈 0.05）. And in male, the estradiol concentration in the hemolymph of immature crab was （ 122.66 ?17.43 ） pg?mL^-1, which was significantly lower than those of precocious and mature crab（ （234.75?22.91 ） pg?mL^-1 for the precocious gonad and （ 237.62?23.51 ） pg?mL^-1 for the mature gonad）（P〈0.01）. The hemolymph estmdiol level of male precocious crab was almost the same as that of the male mature crab, though the estradiol level in the testes of the former was higher than the latter（ 149.96 ? 23.23） pg?g^-1 for the precocious crab and （128.48?26.05）pg?g^-1 for the mature crab）（P 〈 0.05）. These results revealed that estradiol plays a prominent role in the precociousness of Chinese mitten-handed crab （ Eriocheir sinensis ） and the increases of the estradiol level in the crab probably lead to the precociousness of the crab.

Abstract:An experiment was conducted to evaluate the effects of degossypolled cottonseed meal （DCM） on Japanese sea bass （Lateolabraxjaponicus,（5.04?0.02） g initial body weight）. Five experimental diets DCM 0, DCM 25, DCM 50, DCM 75A, DCM 75 were formulated to contain 0, 15.2%, 30.5%, 46%, and 46% DCM to replace 0, 25%, 50%, 75%, 75% fish meal protein respectively, and the DCM 75 A was supplemented with lysine and methionine to be similar to DCM 0 for Japanese sea bass. Three tanks were randomly assigned to each diet, and 16 fish were batch weighed and stocked into each tank. Faecal were collected after 2 weeks of normal feeding for nutrients apparent digestibility coefficients （ADCs） determination, and the growth trial lasted for 8 weeks. The results showed that fish fed diets DCM 50 had significantlyhigher feed conversion ratio （FCR） and lower protein efficiency ratio （PER） than that of DCM 0 group （ P 〈 0.05）. Fish fed DCM 75A and DCM 75 diets had significantly lower growth performances than those of fish fed diet DCM 0 （ P 〈 0.05 ）, but the lysine and methionine supplement improved PER of diet DCM 75A diet. There were no significant differences in ADCs of dry matter, crude protein, crude lipid, energy and body composition. The present results indicate that DCM may be included in the diet up to 30.5 % as a substitute for fish meal, and it can replace about 50 % of fish meal protein.