Effects of Ovarian Preservation Time on in vitro Maturation and in vitro Fertilization of Oocytes from Slaughtered Sheep

[Objectives] The aim was to study the effects of ovarian preservation time on in vitro fertilization of oocytes from slaughtered sheep. [Methods] The collected ovaries were randomly and evenly divided into four groups. They were preserved in physiological saline containing penicillin（ 100 IU/ml） and streptomycin（ 100 μg/ml） at 15-20 ℃ for 0（ Control）,6,12 and 18 h,respectively. Then,the oocytes were subjected to in vitro fertilization. [Results]The maturation rates,cleavage rates and blastocyst rates of the oocytes preserved for 6 and 12 h showed no significant differences compared with those of the oocytes preserved for0 h（ 72. 03%,70. 87% vs. 73. 68%; 74. 12%,72. 60% vs. 74. 49%; 22. 22%,20. 75% vs. 23. 29%）（ P 〉 0. 05）. There were also no significant differences in maturation rate,cleavage rate or blastocyst rate between the oocytes preserved for 18 and 0 h（ P 〉 0. 05）. [Conclusions] Within a certain rage（ 0-18 h）,storage time of ovary at 15-20 ℃ does not affect the continued development of oocytes from slaughtered sheep.