Production of zona-free cloned bovine embryos

Abstract

The objective of this work was to apply a new zona-free cloning method for producing cloned bovine embryos. The procedure of the method included enucleation of matured oocytes without zona pellucida using a microblade or micropipette; electrofusion of oocyte-donor cell pairs; in vitro culture in microwell system. By this method, the percentage of enucleated oocytes was 84.89%, and the percentage of fused oocytes with donor cells was 86.91%. After fusion, oocytes fused with donor cells were selected for activation and in vitro culture in SOFaa medium. At 18 hours after activation and culture, the rate of reconstructed oocytes was 88.89%. The development rates of cleavage and blastocyst embryos were 87.61 and 24.78%, respectively. In conclusion, the method of zona-free cloning of bovine embryos was conducted successfully in our lab. This method could be an easy, simple, fast, and efficient operation.