Production of Embryos by Interspecies Somatic Cell Nuclear Transfer (iSCNT) Between Bovine (Bos taurus) and Ovine (Ovis aries) Using Handmade Cloning (HMC)

Objective: To determine the ability of the sheep oocyte (Ovis aries) to generate cloned bovine embryos (Bos taurus), through interspecies Somatic Cell Nuclear Transfer (iSCNT) by Handmade Cloning (HMC). Design/methodology/approach: For iSCNT, fifth-passage bovine skin fibroblasts were used as karyoplasts, and in vitro-matured, manually enucleated ovine oocytes were used as cytoplasts. Cytoplast-karyoplast-cytoplast triplets were formed, which were fused by electrical pulses and activated for the development of cloned bovine embryos, which were cultured in Cleavage medium. Additionally, some ovine oocytes were activated as parthenogenetic embryos to serve as a control group. The in vitro development rate (IVD) of the iSCNT group (BOV-OV) vs. parthenogenetic ovine embryos (G-OV) was evaluated using a two-way Student t-test for paired data. Results: It was observed that in the BOV-OV group, bovine cloned embryos produced by iSNCT using HMC only reached the morula stage (20 blastomeres), while in the G-OV blastocysts were observed with significant differences (p ≤ 0.05). Limitations on study/implications: Limited sample size of slaughterhouse ovaries. Findings/conclusions: Although ovine oocytes were able to initiate the IVD of cloned bovine embryos produced by iSCNT using HMC, species divergence proved to be a critical limiting factor for reaching the blastocyst stage