The aim of the present study was to investigate the cleavage pattern, its developmental ability and apoptosis of porcine embryo in vitro. Morphology data on a total of 919 embryos were analyzed retrospectively. Forty-eight hours after insemination, embryos were classified into five groups based on the cleavage state as follows; 1 cell, 2 cell, 4 cell, 5 to 8 cell and fragmentation. These groups were cultured another 120 hours and then evaluated for blastocyst formation. Blastocyst formation rates were significantly higher in 4 cell (42.5%) and 5 to 8 cell (48.6%) cleaving groups than in other groups (p<0.05). On the other hand, 2 cell and fragmentation groups produced 4.9% and 3,9% blastocysts, respectively. And we could verify that in the event of 2 cell block and fragmentation of embryo. To analyze the apoptotic frequency in preimplantation development of porcine IVF embryos, all cells of each blastocyst were performed by TUNEL assay. There were no significantly differences in the total cell numbers of embryos and apoptotic cell rate in blastocysts among the each classified groups. Data suggest that 4 cell and 5 to 8 cell cleaving embryos at 48 hour after insemination have high developmental competence, and may be an useful parameter to predict the development of preimplantation embryos and to study using preimplanation embryonic research.

Keywords: pig, IVF embryos, cleavage pattern, apoptosis