Effects of the presence and the numbers of corpora lutea in non-delivered and delivered pigs on in vitro oocyte maturation and embryonic development.

The aim of this study was to investigate the effects of the presence and the numbers of corpora lutea (CL) in porcine ovaries on in vitro oocyte maturation and embryonic development following intracytoplasmic sperm injection (ICSI). At oocyte collection, the ovaries of non-delivered and delivered pigs were classified into four groups by CL presence. The effect of the number of CL was also investigated following re-division of the non-delivered groups into four groups. In addition, the progesterone (P(4)) concentrations in follicular fluid (FF) of all the groups were measured to confirm the relationship between the presence and numbers of CL. Throughout the present study, the oocytes recovered from the CL-holding ovaries showed high (P<0.05) oocyte maturation rates, blastocyst rates and P(4) concentrations in FF. Furthermore, in the non-delivered groups, the blastocyst rates and P(4) concentrations in FF seemed to coincide with the CL numbers in each ovary. From these findings, we concluded that the presence and number of CL in the ovary can be used as an indicator for estimation of the developmental competence of porcine oocytes. Additionally, the present study suggests that P(4) in FF influences in vitro oocyte maturation and embryonic development in porcine in vitro production.