Feasibility of long-term ovine epididymal spermatozoa preservation in a simple extender containing egg yolk

Spermatozoa contained in the cauda epididymis could be recovered and used at post-mortem in the situations that the ejaculated sperm are not available such as the sudden death of genetically invaluable livestock males and in endangered wild species. To benefit from the potentials of epididymal spermatozoa, it is important to have suitable protocols for handling and storage of this type of spermatozoa, because the quality of epididymal spermatozoa is affected by the storage conditions. Therefore, the present study was aimed to investigate whether ram epididymal spermatozoa could be preserved in a simple extender containing egg yolk for 120 h at 5˚C. Epididymal spermatozoa were collected from the tails of the epididymides of slaughtered rams and diluted in Tris-citric acid-fructose extenders containing 0, 10, or 20% EY at 1×108 spermmL-1. Afterwards, the diluted samples were stored at 5˚C for 120 h. The motility, functional membrane integrity, and morphology of spermatozoa were assessed at 0, 2, 24, 48, 72, 96, and 120 h of storage period. The results showed that storing ovine epididymal spermatozoa without EY was not possible. In the extender containing 20% EY, membrane integrity was similar to the fresh samples up to 72 h, normal morphology up to 96 h, and progressive motility up to 72 h.