奶牛活体采卵-体外受精效率的影响因素研究

为建立稳定高效的活体采卵-体外受精技术体系，提高体外胚胎生产效率，本研究先利用屠宰场采集的新鲜卵巢卵母细胞进行体外受精，通过胚胎发育潜力来筛选最佳的体外胚胎培养液；再进一步研究不同种公牛精液和供卵母牛对活体采卵-体外受精效率的影响。结果显示，CR1aa培养液和mCR1aa培养液卵裂率差异不显著（P>0.05），但mCR1aa组的囊胚发育率显著提高（28.1% vs 20.6%，P<0.05）；选取的3头荷斯坦种公牛精液的活体采卵-体外受精胚胎的卵裂率差异不显著（P>0.05），但1号种公牛精液体外受精后囊胚率（38.7%）显著高于2号和3号（23.8%&22.9%）（P<0.05）；随机选择的3头活体采卵供体母牛（H1、H2、H3）获得的头均可用卵母细胞数无显著差异，但H1和H2供体母牛体外受精胚胎的卵裂率和囊胚率均显著高于H3供体牛（P<0.05），且H1供体牛体外受精囊胚率显著高于H2供体牛（P<0.05）。结果表明，mCR1aa培养液能显著提高体外受精囊胚发育率，适用于体外胚胎生产；种公牛精液和供体母牛个体差异会直接影响活体采卵-体外受精胚胎的生产效率，为奶牛活体采卵-体外受精生产技术体系的优化提供参考。

Study on the Influencing Factors of in vitro Fertilization Efficiency in Dairy Cows

The aim of this study was to optimize the ovum pick-up(OPU)and in vitro fertilization system,and further improve the in vitro embryo production efficiency.The optimal in vitro culture medium was screened out by using fresh ovaries collected from slaughterhouses for in vitro fertilization.The effects of different bull semen and donor cows on the outcome of in vitro fertilization of oocytes collected by OPU were analyzed.The results showed that compared with CR1aa medium,mCR1aa medium had no significant effect on cleavage rate,but the blastocyst formation rate was significantly increased(28.1%vs 20.6%,P<0.05).Three Holstein bulls semen were randomly selected for in vitro fertilization,the proportion of cleaved embryos was not affected,but the blastocyst development rate of in vitro-produced embryos originating from No.1 bull semen(38.7%)was significantly higher than that of No.2(23.8%)and No.3 bull semen(22.9%)(P<0.05).There was no significant difference in the average number of recovered oocytes obtained from three randomly selected donor cows(H1,H2 and H3),but the developmental ability of embryos after in vitro fertilization was significantly different.The cleavage rates blastocyst rates of H1 and H2 donors were significantly higher than that of H3 donors(P<0.05),and the blastocyst rate of H1 donor was significantly higher than that of H2 donor(P<0.05).In summary,mCR1aa medium significantly increased the blastocyst development rate,and could be used for in vitro embryo production,the individual variability in bull semen and donor cows could directly affect the production efficiency of in vitro embryo production.The results provided a reference for the optimization of OPU-in vitro fertilization technology.