EFFECTS OF OVIDUCTAL FLUID AND HEPARIN ON FERTILITY AND CHARACTERISTICS OF PORCINE SPERMATOZOA

The objective of this study was to determine the effects of oviductal fluid and heparin on sperm penetration and the characteristics of sper matozoa. The addition of oviductal fluid and heparin to the fertilisat ion medium decreased sperm penetration and the mean number of spermato zoa in penetrated eggs. The number of spermatozoa firmly bound to zona pellucida was also decreased in the presence of oviductal fluid and h eparin. Chlortetracycline (CTC) fluorescence patterns were used to det ermine the incidence of capacitation and the acrosome reaction. The pr oportion of capacitated and acrosome-free spermatozoa increased when s permatozoa were exposed for 1.5 and 3h to oviductal fluid and heparin. In contrast heparin alone did not increase the number of capacitated spermatozoa at these time points. These results suggest that factor(s) in oviductal secretions reduce polyspermic fertilisation and the numb er of spermatozoa that will penetrate porcine oocytes. The reduction o f polyspermic penetration by oviductal secretions may be due to a redu ced number of spermatozoa in the fertilisation medium with an intact a crosome.