Study On Nutrient Deposition,metabolic Response Of The Body And Related Mechanism During Ovary Development Stages ?--? In Chinese Sturgeon(Acipenser Sinensis)

Since the construction of Gezhou Dam and other water conservancy projects in the 1980 s,the number of wild Chinese sturgeons(Acipenser sinensis)has declined sharply,thus captive breeding has been explored for the species protection.Unfortunately,there is an obstacle that the gonad maturation of cultured female Chinese sturgeons is difficult in captive breeding.The physiological mechanism of gonad maturation in this species is unclear,and the influencing factors may be temperature,light,nutrition,etc.Considering the nutrition and metabolism of broodstocks,in the present study,the female Chinese sturgeons with their ovaries at stage ?,stage ? and stage ?,respectively,were sampled for the following studies.Firstly,analyses of serum biochemical components and serum metabolomics were conducted;secondly,histological observation and relative lipid droplet content analysis of muscle,histological observation of ovaries(oocytes),and expression analyses of genes related to energy(AMPK)metabolism,lipid metabolism,yolk protein deposit and arginine metabolism in the ovary were performed.Combining the two parts,the characteristics of nutrient deposition,metabolic response of the body and related mechanism during ovarian development of Chinese sturgeons were investigated.The results are as follows:1 In the female Chinese sturgeon,during ovarian development of stage ?-?,the high content of total protein,triglyceride,low density lipoprotein(LDL)and most amino acids in the serum occurred at stage ? and/or stage ?,thus the accumulation of nutrients in the ovary probably occurred mainly at stage ? and stage ?.The serum content of lipoxins,metabolites related to folate biosynthesis,alanine,histidine and taurine were relatively high when the ovary developed to stage ?,which may play special physiological roles in oocyte maturation and ovulation.2 During stage ?-? of the ovarian development of female Chinese sturgeon,the oocyte volume increased dramatically and in which a large number of lipid droplets and yolk protein granules deposited.Meanwhile,as the ovary developed,the relative area of lipid droplets in muscle slices decreased,which suggested the migration of lipid droplets in muscle to the ovary.3 The expressions of genes related to AMPK regulation,lipid metabolism and yolk protein deposition in the ovary proved that,due to the deposition of lipid droplets and yolk protein during stage II-III,the energy requirement for ovary also increased,and the lipid synthesis and decomposition were in active dynamic changes to maintain the overall metabolic balance.4 The expressions of genes related to arginine metabolism proved that,arginine may be an important amino acid in the gonadal development of female Chinese sturgeons,which may be related to its various physiological functions,including synthesis of polyamines and creatine.The conduction of this study will provide a theoretical basis for exploring the regulation mechanism of gonadal maturation in female Chinese sturgeons,and contribute to the elimination of ovarian development disorder in female Chinese sturgeon.