ZONA-PENETRATION IN-VITRO TEST FOR EVALUATING BOAR SPERM FERTILITY

We investigated the capacity of porcine sperm-zona binding and penetra tion by using bioassay to differentiate between spermatozoa from ferti le and subfertile boars. Semen was collected from Large White boars gr ouped into categories of fertile and subfertile (n = 5 per each group) according to the results of artificial insemination. Boars in both gr oups showed similarly hyperactivated sperm motility at insemination (4 4.72 and 43.03% respectively) regardless of the lower percentage of pr ogressive motility observed in the ejaculates of subfertile boars. At in vitro insemination, a high proportion of the sperm population (43.7 6%) in the subfertile boars was without acrosomes, while in the fertil e boars this proportion was only 24.35%. The sperm penetration rate of fertile boars reached 66.03% while that of subfertile boars was only 25.08%. In conclusion, the results of our study showed that the penetr ation rate by boar spermatozoa of the zona pellucida can be used to pr edict fertility and/or as an in vitro standard for describing porcine semen characteristics.