First polar body morphology affects potential development of porcine parthenogenetic embryo in vitro

Previous studies have reported that the first polar body (PB1) morphology reflects embryo development competence, but the effects of PB1 on porcine embryo development remain unknown. This study aims to determine whether the ability of porcine embryo development is related to oocytes' PB1 in vitro. The distribution of type II cortical granules (CGs) of porcine matured oocytes in grade B PB1 is significantly greater compared with those in grades A and C PB1 (71.43% versus 52.46% and 50%; P 0.05). The acetylation level of porcine embryos in the group with grade B PB1 is significantly greater compared with those in the other groups (P < 0.05), and is almost 2.5 times higher than that in grade A. Therefore, porcine oocytes with PB1 in grade B are more competitive in cytoplasmic maturation and further embryo development in vitro.