CHARACTERISTIC OF FROZEN-THAWED EPIDIDYMAL SPERMATOZOA AND REFRIGERATED STORAGE OF RAM SPERMATOZOA

Abstract

Post-mortem spermatozoa recovery is an important technique for obtaining germplasm reserves from genetically valuable animals or endangered species. The purpose of this study was to study whether ram spermatozoa within epididymides stored at 4º C for 24 and 48 h remain their motility and viability. The characteristic of ram epididymal spermatozoa after freezing and thawing was also observed. Six pairs of ram testes with attached epididymides were used in this study. The motility of control spermatozoa was well maintained throughout the dilution procedure (83.3±1.1, 80±1.3, and 80±1.3% for collection, Niwa and Sasaki freezing -1 extender (NSF-1 and NSF-2 groups respectively); but declined (P<0.05) after freezing and thawing (38.3±3.1%). Motile and viable spermatozoa could be recovered from epididymides up to 48 h of storage, although their quality declined significantly (P<0.05) as post-mortem storage time increased (motility: 83±1.2, 67±3.0, and 46±5.1; viability: 84.2±2.4, 73±2.8, and 66.6±2.6 % for control, 24 h and 48 h group respectively). These data indicate that ram epididymides could be stored at 4º C for 48 h when epididymal spermatozoa cannot be immmediately collected and cryopreserved. These storage conditions might be possible to use for epididymal sperm recovery in wild ruminants. Keywords: epididymal spermatozoa, Freezing, ram, refrigeration