Effect of Catalase and Anaerobic Conditions upon the Post-thawing Survival of Bovine Spermatozoa Frozen in Citrate- and Tris-buffered Yolk Extenders

Abstract

Summary Semen samples from six different bulls were extended in citrate-fructose-yolk-glycerol (CFYG) and Tris-fructose-yolk-glycerol (TFYG) extenders with and without catalase, sealed under a high partial pressure of purified nitrogen or argon gas, and equilibrated with glycerol for 6 or 18 hr, and then frozen at rates of 0.8, 3.0, and about 8.0 C per min in the critical region from 5 C to −15 C. The mean percentages of motile cells in TFYG and CFYG were, respectively, 36 and 31 immediately after thawing and 31 and 22 after a post-thawing storage period of 24 hr at 5 C. Thus, the percentage of motile cells in TFYG 24 hr after thawing was equal to that found in freshly thawed CFYG. Neither catalase nor the inert gases exerted a significant influence upon post-thaw recovery of motile spermatozoa, although in the absence of catalase argon gassing showed a positive effect during the period of liquid storage. The slight differences between the periods of glycerol equilibration and among freezing rates were not significant.