Survival of Canine Epididymal Sperm under Cooled and Frozen-Thawed Conditions

Abstract

The objective of the first experiment was to determine the effects of storage at 22„aC vs. 4„aC on the motility and percentage of membrane-intact sperm (%MIS) of epididymal mouse sperm. Testicles were allocated into 22„aC or 4„aC treatment groups and stored for 24 or 48 hours. Additional testicles were allocated into the 4„aC treatment for storage for 72 or 96 hours. Sperm was collected and analyzed at each time point. Storage at 22„aC lowered motility and %MIS (P<0.05) when compared with control sperm and 4„aC sperm at both the 24 and 48 hours. Motility and %MIS of 4„aC sperm did not decrease when compared with the control until after 72 hours of storage. The second experiment evaluated the effects of 22„aC vs. 4„aC storage for 24 and 48 hours on epididymal dog sperm. Motility and %MIS of the 22„aC sperm was lower than that of the 4„aC sperm and the control (P<0.05) at 24 and 48 hours. Motility of the 4„aC sperm was lower than the control at 24 and 48 hours (P<0.05), however %MIS was not lower than the control until 48 hours. The third experiment tested the effect of cryopreservation on epididymal dog sperm. Sperm was frozen immediately (A), after 48 hours at 4„aC in liquid (B) or after 48 hours at 4„aC of the whole testicle (C). Both pre-freeze (PF) and post-thaw (PT) motility and %MIS of B and C were lower than A (P<0.05). PT values were lower than PF values in all treatments (P<0.05). PT motility of B was lower than C (0 vs. 35.0¡Ó3.6%). Storage at 4„aC allows collection of motile epididymal mouse and dog sperm for several days after death. Dog testicles can be refrigerated for 2 days and epididymal sperm frozen with PT motility and %MIS of 35 and 62%.