Effect of prostatic fluid on motility, viability and acrosome integrity of chilled and frozen-thawed dog spermatozoa.

Sperm preservation has become a routine procedure in dog breeding. In this study, the influence of prostatic fluid on sperm characteristics after preservation (either chilling or freezing) was investigated. The sperm-rich fractions of 20 ejaculates from five dogs were either extended without centrifugation or centrifuged and resuspended either directly in extender or in prostatic fluid before dilution with extender. Aliquots were processed for storage at 4 degrees C for 6 h or for freezing. Storage at 4 degrees C did not affect sperm motility, viability or acrosome integrity, irrespective of the dilution treatment. However, sperm motility and viability decreased significantly after freezing and thawing, particularly in the samples with additional prostatic fluid. In contrast, the acrosome morphology of viable spermatozoa was not affected by either the dilution method or by chilling or freezing and thawing. It is concluded that addition of prostatic fluid during semen processing adversely affects the motility and viability of frozen-thawed spermatozoa. However, prostatic fluid does not appear to affect the motility and viability of chilled spermatozoa or to alter acrosome integrity in either system of preservation.