Different Maturation Factors On Early Embryonic Development In Yanbian Cattle Oocytes In Vitro Maturation And Nuclear Transfer

The ovaries of slaughtered Yanbian cow were acquired in this experiment, the oocytes were matured in vitro (IVM) in different conditions, then carry though nucleus transfer, fusion, activation and in vitro culture of embryo (IVC). In this experiment, compared the effects of seasons, temperature, treatment time, maturation time, corpus luteum and diameter of follicle on maturation rate, cleavage rate, development rate in 4-6C and 8-16C. The results are as follows:(1) The experiment is carried out in four different seasons, we can get: the maturation rate, cleavage rate, development rate of 4-6C were highest in fall, exists significant difference with others. So the results were best in autumn.(2) The maturation rate was 47.25% when the ovaries were stored at 20-29℃, cleavage rate was 40.82%; the maturation rate of group of 30-39℃was 44.60%, cleave rate was 44.63%; development rate of 4-6C was 37.04% and 45.00% respectively, have no significant difference between them. This shows: the stored temperature at 20-39℃have no significant effect on IVM of oocytes and development of early stage embryos after nucleus transfer.(3) According to treatment time the experiment was divided into Group 1h, Group 2h and Group 3h. The maturation rate of Group 1h and Group 3h were 62.95% and 59.74% respectively, have no difference between them; the Group 2h was highest, for 74.45%, but have significant difference with Group 1h(P＜0.05). The cleavage rate were 55.87%, 55.16%, 49.84%; development rate of 4-6C were 42.86%, 41.46%, 35.85%; development rate of 8-16C were 30.25%, 24.39% and 23.90% respectively. In these threes groups have no significant difference.(4) As mature time the experiment was divided into 18-20h,20-22h and 22-24h three groups, their maturation rate were 69.33%, 77.35%, 81.52%, in which the lowest was the 18-20h, the highest was the 22-24h, have no significant difference between them; the cleavage rate was in reverse, the highest was the 18-20h (53.38%), the lowest was 22-24h (49.07%), have no difference; development rate of 4-6C were 42.25%, 43.64%, 37.74%; development rate of 8-16C were 16.90%, 18.18% and 26.42%, have no significant difference also.(5) According to the corpus luteum on ovary surface, divide the experiment into with corpus luteum (+) and without corpus luteum (-). The maturation rate of them were 60.63% and 62.75%, development rate of 4-6C were 34.41% and 37.23%; development rate of 8-16C were 26.89% and 17.52%, all have no significant difference; the cleavage rate of without corpus leteum higher than with corpus luteum, but have no significant difference.(6) Has three groups:＜4mm group, 4-6mm group,＞6ram group. The maturation rate were 60.74%, 59.34%, 69.17%; cleavage rate were 62.42%, 71.11%, 49.06%, development rate of 4-6C were 36.56%, 57.81% and 53.85%, developed rate of 8-16C were 20.43%, 21.88% and 23.08%, have no significant difference。The results shows: different diameter of follicles on ovary surface have no effect on IVM of oocytes and development of early stage embryos after nucleus transfer.