Abstract
Potential of a new sperm quality test, "In vitro sperm-egg interaction assay", for evaluating the fertilizing ability of spermatozoa from individual drakes was examined. The inner perivitelline layer (IPVL) separated from egg yolk was incubated with spermatozoa from individual drakes, and the number of holes formed on the IPVL by sperm hydrolysis in vitro were counted. At the same time, the sperm samples were subjected to motility, viability and fertility tests. The number of holes hydrolyzed on the IPVL in vitro by spermatozoa showed significant difference among the 6 males tested. The number of holes in the IPVL was highly correlated with the fertility of the eggs laid by inseminated females (r=0.90, P<0.001). On the other hand, sperm motility and viability varied little among the tested males, although the results of the fertility test for the same males varied with individuals (P<0.05). These results suggest that the in vitro sperm-egg interaction assay can describe the difference in the fertilizing ability of spermatozoa from individual drakes more clearly than conventional in vitro tests do. This new technique is considered to be applicable to the preliminary screening of the candidate males in the selection of breeder drakes.
