[Production of porcine reconstructed embryos by whole-cell intracytoplasmic microinjection]

Cloning by somatic cell nuclear transfer has been achieved by both electric fusion and intracytoplasmic nuclear injection (ICNI) methods. However, each of the above methods involves extended complicate manipulation and special equipment. Here we report a whole-cell injection technique without Piezo assistance for nuclear transfer in pigs. The fibroblast cell of pig as the nucleus donor cell, effects of the new method on the efficiency of somatic nuclear transfer in pig were investigated, compared with that of electric fusion method. Results showed that the new method was a little less efficient in producing reconstructed embryos but without significant difference (88.4% vs 78%, P > 0.05). After the embryos were cultured 48h and 7d, the fusion method is more efficient than the new method in the oocyte cleavage rate and the blastocyst development (78% vs 53.2%, P < 0.05; 27.2% vs 13.8%, P < 0.01). The results indicate that both methods make no difference in the quality of the blastula, but the electric fusion method is more efficient. Therefore, the applicability of producing normal,cloned piglets by the simple and less labor-intensive whole-cell intracytoplasmic injection needs further improvement.