Protein Nutrition Of Chinese Mitten-handed Crab, Eriocheir Sinensis

In crustaceans, vitellogenesis is associated with several complete processes that lead to the formation of mature oocytes within the ovary. Substantial quantities of yolk protein (mainly lipovitellin) accumulate within the developing oocytes, and serve to meet the basic requirements of embryonic and early larval development, dependent of the maternal organism. So crustacean broodstock nutrition and feeding have been shown to greatly improve not only egg and sperm quality but also seed production. The availability of an optimal diet is identified as a crucial factor for the sexual maturation and reproduction of shrimp and crab. Gonadal development and fecundity are affected by certain essential dietary nutrients, especially essential amino acids, essential fatty acids, and vitamins etc. Thus, during the last two decades, more attention has been paid to the optimal level of different nutrients in broodstock diets.It is well known that protein is a kind of indispensable nutrient because of its important physiological function on body structure and supplying energy to the growth and development of shrimp and crab. Protein and amino acids of broodstock diet have been identified as major dietary factors that determine successful reproduction and survival of offspring. Up to date there are no reports on optimal protein levels, or amino acid profiles for crustacean (especially shrimp and crab) broodstock diets.The Chinese mitten-handed crab, Eriocheir sinensis, is considered to be one of the most important species for commercial production in China. Nutritional requirement for protein at different grow stages has been studied by many researchers. But at present few attach importance to nutriology and digestive physiology of E. sinensis broodstock. So in this paper, effects of dietary protein levels on the content of protein and amino acid profile in hepatopancreas and ovaries during ovarian maturation are investigated on basis of analyzing protein content and amino acid composition and content in hepatopancreas and ovary of broodstock in nature. Influence of dietary protein on concentration of lipovitellin in ovary of broodstock after purification and preparation antibody of lipovitellin from mature ovaries of E. sinensis is evaluated. And nutritional requirement for arginine and lysine, and interaction between protein and vitamin B6 of juvenile E. sinensis are also studied. Finally digestive enzyme activities in hepatopancreas of E. sinensis fed on experimentdiets with different protein level during juvenile and ovarian maturation. The purpose is to accumulate basal information for reproductive nutrition, and provide reference for breeding broodstock in seed production and formulation of broodstock diet.1. Isolation, purification and characterization of lipovitellin from the ovary of female Eriocheir sinensis broodstockLipovitellin was extracted and purified using gel chromatography and electrophoresis procedures from ovaries of Chinese mitten-handed crab. One kind of lipovitellin was obtained. Lipovitellin could be stained by Sudan black, Stand-all, and Schiff reagent, which indicated that it comprised some component such as lipids, carbohydrate and phosphorus etc. The characterization of lipovitellin was carried out by SDS-PAGE. The results indicated that lipovitellin had a molecular weight of approximately 520.85?9.02kDa and was composed of two kinds of subunits, whose molecular weights were 96.92+2.83 kDa and 73.86?.89 kDa respectively. Major amino acids made up of lipovitellin are aspartic acid (asparagine), and glutamic acid (glutamine), their contents were 10.80% and 14.31%, some amino acids including leucine, lysine, arginine and valine were less, their contents were 9.43%, 7.83%, 7.08% and 6.88%, respectively, while contents of taurine, cysteine and histidine were very low, only 0.17%, 1.01% and 1.40%. The purpose to analyze amino acid profile of lipovitellin is to provide a kind of reference standard for broodstock amino acid nutritional requirement. The purified lipovitellin can be used...