AGEING OF RABBIT SPERMATOZOA IN THE MALE TRACT AND ITS EFFECT ON FERTILITY

Abstract

Summary. The influence on fertility of the ageing of rabbit spermatozoa in the male tract has been investigated. To age the spermatozoa, the corpus epididymidis was ligated bilaterally so that the inflow of younger spermatozoa into the tail of the epididymis from higher levels of the duct was prevented. Ejaculated semen samples collected from the rabbits at different times after the operation were used for insemination. It was found that the fertilizing capacity of the spermatozoa was lost after 49 days. Losses before implantation increased progressively until 28-day-old spermatozoa were used, but post-implantation losses reached a peak with 35-day-old spermatozoa. After implantation, losses appeared to occur at progressively earlier stages of development as the age of the spermatozoa increased. In the strain of rabbits used, several foetuses were seen to lack gall bladders and to have abnormal skull sutures following the insemination of does with aged spermatozoa. Throughout the experiment, the motility, morphology and reaction of the spermatozoa to staining with aqueous nigrosin—eosin was examined. The significance and possible causes of adverse changes in ageing spermatozoa are discussed.