The present study was carried out to examine ovarian response to a combination of pregnant mare's serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG), oocyte maturation
in vivo or
in vitro, and the
in vitro fertilization rate of
in vivo and
in vitro matured oocytes of prepubertal Jinhua pigs at 70-75 days of age. Eighteen of the 19 pigs treated with gonadotropins had follicles larger than or equal to 7 mm in diameter, and 4 pigs ovulated 36-42 h after hCG injection. The rate of nuclear maturation in the oocytes from large ( ?? 7 mm) follicles (81%) was similar to that in oocytes from small (2-6 mm) follicles of control animals and cultured
in vitro (83%), and the rate of sperm penetration in oocytes matured
in vivo (88%) did not differ significantly from that oocytes matured
in vitro (97%). However, the rates of male pronucleus formation and monospermy were significantly higher in oocytes matured
in vivo (89% and 31%) than in oocytes matured
in vitro (56% and 9%). These results show that follicular oocytes in prepubertal Jinhua pigs at 70-75 days of age can mature equally
in vivo and
in vitro, but the fertilizability of oocytes matured
in vivo is superior to that of oocytes matured
in vitro.
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