Freezability, enzyme leakage and fertility of buffalo spermatozoa in relation to the quality of semen ejaculates and extenders

Abstract

Forty-eight semen ejaculates from four Surti buffalo bulls were studied under split sample technique to establish the effects of initial semen quality and tris fructose yolk glycerol (TFYF), egg yolk citrate glycerol (EYCG) and lactose yolk glycerol (LYG) extenders on the freezability, fertility (based on 3412 AI) and extracellular release of spermatozoal enzymes pre and postfreezing. The overall mean activity of GOT, GPT, AKP, ACP and LDH enzymes in the postthaw seminal plasma increased significantly (P<0.01) above prefreeze levels, whereas sperm motility decreased. Freezability and the release of these enzymes were not influenced by the types of extenders used except for AKP release, which was significantly (P<0.01) lower in TFYG diluent. The pre and postfreeze sperm motility was significantly higher (P<0.01) and the leakage of GOT, AKP and ACP was lower in 36 semen samples with an initial motility above 70% than in the 12 samples in which initial motility was between 60 and 70%. The effects of interactions between motility groups, diluents and freezing periods were statistically nonsignificant for both freezability and leakage of all five enzymes. Fertility rate of frozen semen produced in TFYG diluent was significantly (P<0.05) higher (42.69%) than in the other diluents and was followed by that of EYCG (39.78%) and LYG (37.50%) with an overall mean of 40%. Sperm post-thaw motility had significantly (P<0.01) negative correlations with the release of enzymes: GOT (−0.948); GPT (−0.859); AKP (−0.673); ACP (−0.951) and LDH (−0.764). Fertility rates showed high negative correlations with the release of all five enzymes. Freezability was positively correlated with fertility (+0.405). Significant positive correlations were also observed for the release of GOT with that of GPT (+0.944); AKP (+0.574); ACP (+0.911) and LDH (+0.839): GPT with ACP (+0.795) and LDH (+0.870): and ACP with AKP (+0.725) and LDH (+0.577). These findings stressed the use of simple estimates of GOT and AKP leakage as markers for the assessment of freezability and fertility, and also the importance of initial good quality semen and the suitablity of extenders (TFYG) in the production of frozen buffalo bull semen for better fertility rates.