Study On The Gonad Development Regularity And Artificial Reproduction Of Andrias Davidianus

Andrias davidianus is the biggest amphibian in the world. It's protected as the secondary-order animal, in China. Many scholars have made survey and studies on the gonad development, farming and artificial reproductive of it and enriched the biological resources of it. For the deep study on the reproductive biological regularity of it and also exploration to the reason why the artificial insemination rate was low, we made a lot of studies and exploration on the hand of gonad development and artificial reproduction of it. The results were summarized as follows: 1 The gonad development of Andrias davidianus 1. The test is development of Andrias davidianusThe test is was covered with serous membrane in the surface. The essensce of testis consisted of seminiferous and loose connective tissue between seminiferous and the seminiferous epithelium in seminiferous consisted of spermatogenic cells and supporting cells. The spermatogenic cells developing from spermatogenous cells to mature spermatozoon included five phases and it was similar with other vertebrate. When the spermatozoon was not mature, they juxtaposed with tales on one side and heads on the other side. And it was different with othervertebrate. The spermatozoon consisted of a head, a middle piece and a tail. In the head there was a stick-like nucleus with highly condensed chromatin in it. There was a fossa in the end of the head and centrioles and mitochondria were located in the fossa. The tail of the spermatozoon was thin and long and with an undulating membrane. 2. The ovary development of Andrias davidianusOn the condition of artificial farming, it was distinctive that the season regularity of the development of ovary. The ovary development was divided into six phases. In the nuclear of II phase ovocyte, there were many lamp brush chromosome, and from III phase ovocyte there were some yolk, the yolk were farctus in IV phase ovary. 2 The artificial reproduction of Andrias davidianusWith the method of artificial ripening, we carried out artificial reproduction of Andrias davidianus. We found that the reproductive season of it were June, July and August and with the water temperature of 20. 5 + 0. 5C, Andrias davidianus embryogenesis needed 27 to 29 days.