Abstract
To investigate whether preincubation of spermatozoa was a prerequisite procedure for successful in vitro fertilization (IVF) in the pig, we inseminated in vitro-maturing oocytes with either Percoll-washed or control-washed (diluted-and-pelleted) boar spermatozoa without preincubation. Both forms of washing were carried out in Tyrode's-based medium, and IVF was performed in modified Tyrode's solution containing 2 mM caffeine, 4.6 mM calcium and 5 mg BSA/ml. Percoll-washed and control-washed spermatozoa penetrated 94-100% and 95-97% of GVBD (germinal vesicle breakdown) oocytes, respectively, and the speed of penetration was similar for the 2 preparations. These results show that boar spermatozoa can penetrate oocytes in vitro without preincubation, and there was no difference in the oocyte penetration rate between those inseminated with Percoll-washed and those inseminated with control-washed (diluted-and-pelleted) spermatozoa.
