K. U. E. Perera, H. B. S. Ariyaratne
Abstract: Cryopreservation of epididymal sperms in domestic and non-domestic animals has a number of important practical applications such as preservation of valuable genetic material from non-breedable animals. In the present study, the motility, morphology and viability of sperms obtained from head, body and tail of the epididymis were studied before and after freezing using eleven samples of goat epididymis collected from the Kandy abattoir soon after slaughter. To assess the changes of morphology and viability, smears stained with Eosin and Nigrosin were used. Statistically significant differences were observed in the motility and viability of sperms in the head, body and tail of the epididymis (P< 0.05) before and after freezing. Before freezing, the highest motility and viability were detected in sperms collected from the tail of the epididymis. The values observed were 75.45 5.22 % and 78.18 5.65 % for motility and viability respectively which reduced up to 39.09 8.31 % and 37.72 4.96 % after freezing. The lowest motility and viability were observed in sperm of the head of the epididymis, which were 5.27 2.72 %, and 47.27 10.52 % respectively and reduced up to 1.00 0.89 % and 24.18 6.90 % after freezing. The motility and the viability of the sperms in the body of the epididymis were found to be 26.36 16.29 % and 49.54 8.57 % and reduced up to 4.36 2.38 % and 32.54 6.79 % respectively due to freezings. Freezing resulted in increased head and tail abnormalities of sperms such as small heads, acrosomal defects, coiled tails and bent tails (P<0.05) in sperms collected from all three parts of the epididymis. A significant difference was detected in the proportion of sperms having proximal cytoplasmic droplet among the head, body and tails of the epididymis (P< 0.05), whereas no such difference was observed for the distal cytoplasmic droplet in sperms collected from different regions (P> 0.05) before freezing. Similar trend was also observed in sperms collected from these regions after freezing. Analysis of variance revealed that a significant interaction existed between the treatment and the region of the epididymis for the parameters of motility, viability and acrosomal defects (P< 0.05). From these observations, it was concluded that the cryopreservation was most successful when the sperms were obtained from the tail of the epididymis.
Keywords: Acrosomal defects, Cryopreservation, Cytoplasmic droplet, Epididymis, Sperms