In Vitro Maturation And In Vitro Fertilization Of Oocytes From Goat And Zygotes In Vitro Culture

Experiments were conducted to investigate maturation, fertilization and culture in vitro of oocytes from ovaries which compared to some oocytes collected from superovulation.Goat ovaries were collected from slaughterhouses.Follicular oocytes were recovered using three different methods: aspiration, dissection and puncturing. The average total number of oocytes recovered per ovary was significantly higher by the aspiration method,but time required for processing each ovary and usable oocytes by the aspiration were comparatively more,so aspiration is not a good method to recover oocytes. The numbers of oocytes recovered per ovary were 5.6 and 6.7 for dissection and puncturing, respectively. The percentages of oocytes of A, B, C grade for dissection was 49%,43%,8%, and for aspiration was 52%,42%,6%,respectively.There were no significant differences between two methods.But time required by dissection were more than puncturing(P<0.05).Seasons affected recovering oocytes from ovaries.The maturation rate of oocytes during breeding seasons was significantly higher than that during non-breeding seasons. Seasons did not affect the number of matured oocytes of goat of higher superovulation response and common response,but affected significantly on goat of not in oestrus.The number of available oocytes, the maturation rate was not differ significantly of oocytes recovered between pregnant ovaries and not pregnant ovaries.There were different size of follicles in ovaries.The maturation rate of oocytes from large and medium follicles was 96.08%, 68.06%, respectively.Significant difference was observed in the maturation rate(45.90%) of small follicles. The maturation rate of oocytes from large follicles was significantly higher than that ofmedium follicles.But the cleavage rate of oocytes from medium follicles after IVMFC was significantly higher than that of oocytes from large and small follicles.The growth culture medium was supplemented with EGF of 20ng/ml, 30ng/ml, 50ng/ml.The maturation rate was 68.75%,74.19%,79.31%, respectively.The cleavage rate was 43.64%,45.22%,53.91%, respectively. Comparing with control groups, EGF(30ng/ml) significantly promoted maturation of the oocytes,but had no stimulatory effect on cleavage of the zygotes. EGF(50ng/ml) significantly promoted the maturation of the oocytes and the cleavage of the zygotes.Ten zygotes were cultured in microdrop of 30ul,40ul,50ul, respectively. The number of cleavage in microdrop of 30ul was higher than that of microdrop of 40ul and 50ul.There were no significant differences of the cleavage rate among one zygote culturing in 3ul microdrop, five zygotes culturing in 15ul microdrop, and ten zygotes culturing in 30(0.1 microdrop.But with the increase of the number of zygotes, thecleavage rate tended to enhance.