Received: 17-04-2023 / Accepted: 29-08-2023
The research was conducted to improve the quality of in introbovine embryo vitrification. Bovine oocyteswere matured thenfertilizedwith frozen-thawed semen at1, 2or 5× 106sperm/ml for 6 hours to find the optimal conditions. Theblastocysts were then rapidly frozen in the medium using TCM199+BSA (Tissue culture medium-199+Bovine serum albumin) or DPBS+FBS (Dulbecco's phosphate-buffered saline+Fetal bovine serum). There was no significant difference in the maturation rateof oocytes matured in BO-IVM or TCM-199 medium. In vitrofertilized bovine oocyteswith frozen-thawed sperm atconcentration of 2 × 106sperm/ml for 6 hours gave the highest fertilization and blastocyst rate. The survival rate after thawing of bovine embryosfrozenin DPBS+FBS and TCM199 + BSA medium was92.96% and 82.71%, respectively, however, there was no significantdifference between the groups. Thehatching rate after thawing of embryos vitrified in TCM 199 + BSA medium reached 54%, significantly higher than that ofembryos vitrifiedin DPBS+FBS medium (28.8%). Inthe gene-edited embryo group, the number of survival embryos after thawing reached 96.03 % compared to 88.82 % in the IVF group. The source of oocytesalso affected the survival rate of embryos after thawing.