[In vitro development of the reconstructed embryos of cattle activated after various electrofusion times]

The dynamics of in vitro development of reconstructed embryos of cattle after various electrofusion times was studied. The in vitro mature oocytes without zona pellucida enucleated using the touch method were taken as cytoplasts. Fetal fibroblasts were used as the nuclei source. Approximately 40% of embryos activated between 3 and 3.2 hours after electrofusion developed to blastocysts. The effectiveness of in vitro cloned embryo development did not decrease when the time between electrofusion and activation was extended up to 4-5 hours. The pattern of more successful development of in vitro reconstructed embryos was found using enucleated oocytes, excreting the first polar body after 18 hours in comparison with oocytes matured in vitro afterwards, as cytoplasts.