Effect of Ram Breed on the Efficiency of in vitro Development of Sheep Embryos

摘要

The aim of this work was to investigate the impacts of ram breed on in vitro embryo development from fresh or frozen semen. Semen was collected from Najdi and Naimi rams and frozen; the mass and progressive motility of the spermwere assessed in each trial before and after freezing. Then, 970 oocytes in six replicates were fertilized with fresh and frozen semen in vitro. Different stages of sheep embryos were recorded. There were no significant differences in mass and progressive sperm motility of fresh or frozen ram semen between Najdi and Naimi.but there were significant differences between frozen and fresh semen within each breed. Our results showed significant (P＜0.05) differences in 2-cell stage, 4-cell stage, 8-cell stage, morula, fragmented embryos, cleavage and blastocyst rates in the frozen semen group compared to fresh semen group in both breeds. In addition, significant (P＜0.05) differencesbetween the two breeds were shown in 8-cell and 16-cell embryonic stages.In conclusion, there were slight breed effects on the efficiency of in vitro development of sheep embryos.