Abstract
The present experiment was designed to investigate the effect of follicular shell and fluid added to maturation medium on the porcine sperm penetration rate and subsequent male pronucleus formation in oocytes. Pig follicular oocytes were cultured for 47h, with follicular shells, 10% follicular fluid or their combinations added to a medium drop of TCM-199. All treatments had no effect on the proportion of oocytes developing to second metaphase of meiosis. Following insemination, the penetration of oocytes by frozen-thawed sperms was not significantly different among the treated groups. However, the proportion of polyspermic oocytes was significantly lower (p<0.05) when the oocytes were cultured with 10% follicular fluid (25.8%; 16/62) than when they were cultured in other conditions. The percentage of oocytes capable of sustaining male pronucleus formation was higher (p<0.05) when they were cultured with follicular shells combined with 10% follicular fluid (53.8%;43/80) than in all the other maturation conditions. These results indicate that follicular fluid has an effective action on preventing polyspermy in oocytes and that the follicular shells combined with follicular fluid increases male pronucleus formation, inducing the cytoplasmic development of porcine oocytes during their in vitro maturation.
