INFLUENCE OF INITIATION OF FORWARD MOTILITY ON THE FERTILIZING ABILITY OF IMMATURE BOAR SPERMATOZOA IN in vivo HOMOLOGOUS and in vitro HETEROLOGOUS SYSTEMS OF IMSEMINATION

Abstract

The fertilizing ability of spermatozoa is acquired in the epididymis simultaneously with the acquisition of forward motility, and is maximal in fully motile spermatozoa taken from the cauda of the epididymis of the boar (1). The induction of forward motility by rabbit testicular sperm with caffeine has been shown to improve ovum activation in vitro (2). Similarly, after their motility has been increased by treatment with caffeine, the spermatozoa from guinea-pig caput epididymis become as fertile in vivo as the distal cauda sperm (3). In view of these observations, it was proposed to evaluate the fertilizing ability of boar testicular and caput epididymal spermatozoa following the initiation of forward motility with caffeine, either by an homologous oviduct insemination in vivo or by an heterologous fertilization of zona-free hamster eggs in vitro.