Effect of Orvus ES Paste on Acrosome Morphology, Motility and Fertilizing Capacity of Frozen-Thawed Boar Sperm1

In four experiments the surfactant, Orvus ES Paste (OEP) was incorporated in semen extender to determine its effects on acrosome morphology, motility and fertilizing capacity of frozen-thawed boar sperm. In experiment 1, the effects of 0, .5, 1, 1.5 and 2% OEP in the Beltsville F5 (BF5) extender containing 20% egg yolk were compared. Maximum post-thaw results for percentage of acrosomes with a normal apical ridge (NAR) were obtained with 1 to 1.5% OEP. In experiment 2, incubation of boar sperm for 1 hr with as little as .1% OEP in an extender devoid of egg yolk had a marked deleterious effect on acrosome morphology and sperm motility. In experiment 3, the beneficial effect of OEP on acrosomes of boar sperm was more pronounced after the 2-hr cooling rate than after the 6- or 12-hr cooling rates. In contrast, the beneficial effect of OEP on sperm motility was independent of cooling rate. In experiment 4, the competitive fertilizing capacity of boar sperm frozen in BF5 containing 0 or .5% OEP was compared. Number of ova fertilized by sperm frozen with 0 or .5% OEP (43 vs 81) differed from a 50:50 ratio (P<.01). These results indicate that OEP was a beneficial component of the extender and significantly enhanced cryopreservation of boar sperm under conditions employed.