Research On Reproductive Performance In Female Of Hucho Taimen

The H.taimen is a large cold water fish and endangered species in China. Since the problems of artificial propagation and larval fish domestication were solved, conserving recourse and artificial cultivation became to possibility. In recent years, the study showed, artificial breeding of H.taimen had some problem such as ganodal development difference and low hatching rate of some broodfish. Ovarian development regulation and evaluating egg quality as the basement of theory and the leader of practice became the problem that must to be solved as soon as possible. In order to evaluate reproductive performance of female strictly, ovarian development stage, reproductive performance of female in different ages and Relationship between the eyed rate and biochemical composition of egg and ovarian fluid were studiedThe process of ovarian development of Hucho taimen female was divided into six stages. The stage Ⅰ, the ovary was thread-shaped, oogonium arrange on ovarian board compactly; The stage Ⅱ, ovarian was cuticolor, follicle layer became thicker and follicle cell formed, more and more organelle appeared in the oocyte; The stage Ⅲ, the mid of ovarian was bigger, and the ovarian was the faster growth phase. The cells comprise of oocyte of stage Ⅰ-Ⅲ prominently stage Ⅱ and droplets appeared. Organelle developed in the cells and follicle cell became to2-3layers. The stage Ⅳ, the volume of ovarian and ovum diameter increased, and ovarian started to accumulate yolk. The cells were almost oocyte Ⅳ and oocyte was full of droplets. Yolk nucleus disappeared, and granulose cell layer formed. The stage Ⅴ, ovarian was soft, big and jacinth. And it was full of mature oocyte. Yolk and bioplasm polarized apparently. Cell nucleus was transferred and nucleus membrane disappeared. The stage Ⅵ, the color of ovarian was from cuticolor to a little red. Ovarian capacity shrunk, the cells was oocyte Ⅱ and empty follicle cells. The breeding season of H. taimen female was April and May. The ovarian stayed stage Ⅳ in the December. The H. taimen was single spawner, spawning only once a year.Body length and body weight of the female of H.taimen in age six, eight and ten were measured. And egg numbers, ovum diameter, egg weight and eyed rate were detected after artificial breeding. Body length, body weight and egg numbers significantly increase and there are also significant relevance between body length, body weight and egg numbers. The ovum diameter, egg weight and eyed rate increase with the increasing of age extremely the significant difference parameters between age six and age ten females. Differences in fecundity and egg size may be result of body length, body weight and age of female. The reproductive performance of the female of H.taimen is stronger from age six to age ten. In order to understand the relationship between the eyed rate and biochemical composition of egg and ovarian fluid in Hucho taimen, enzyme activities, levels of protein, Amino acids, vitamins and minerals of V stage eggs and ovarian fluid were determined using the method of biochemistry in H. taimen. Regression models for the prediction of the eyed rate using the parameters as independent variables were analyzed. The results showed that significant correlations were found between the eyed rate and Mg2+-ATPase activity, levels of phosphorus and levels of amino acids of eggs. No correlations were found between the eyed rate and egg biochemical composition (proteins, acid phosphatase, alkaline phosphatase, aspartate aminotransferase, Succinate dehydrogenase, calcium ions, iron ions, vitamin C and vitamin E). Mg2+-ATPase activity above8.3×10-5μmolPi/min/mgprot, levels of phosphorus between12.97umol/g egg and23.03μmol/g egg, levels of amino acids between574.89μmol/g egg and1195.40μmol/g egg characterized egg batches with high viability (>80%). In addition, from the investigated parameters of ovarian fluid (proteins, amino acids, acid phosphatase, alkaline phosphatase, aspartate aminotransferase, Succinate dehydrogenase, phosphorus, calcium ions, iron ions, vitamin C and vitamin E) only the aspartate aminotransferase activity was correlated with the eye rate of H. taimen. Aspartate aminotransferase activity above18.14umol/min/L ovarian fluid characterized egg batches with high viability (≥80%). So highly significant correlations was found between the eyed rate and Mg2+-ATPase activity, levels of phosphorus, levels of amino acids of eggs and aspartate aminotransferase activity of ovarian fluid in H. taimen.