Effect of bovine serum albumin in extender on post thaw quality of buffalo bull spermatozoa

Present study determined the effect of adding bovine serum albumin (BSA) at two different concentrations (0.5% and 1.0%) in tris citric acid extender on quality of buffalo bull spermatozoa at post-thawing. Three buffalo bulls of Nili-Ravi breed were used for semen collection with artificial vagina (at 42 degree C). Semen ejaculates with volume greater than 1 ml, motility greater than 60% and sperm concentration greater than 0.5 billion per ml were selected for further processing. Semen from three bulls was pooled, divided into three parts and extended in tris citric acid, yolk extender containing either 0.0% (control), 0.5% or 1.0% BSA at 37 degree C. The extended semen had a concentration of 50x10(6) spermatozoa per ml. Extended semen was cooled from 37 degree C to 4 degree C in 2 h and then equilibrated at 4 degree C for 4 h. After equilibration, semen was filled in 0.5 ml French straws. Semen was frozen by placing the straws in liquid nitrogen vapours for 15 min and then they were immersed in liquid nitrogen (LN) for cryopreservation. After 24 h of storage in LN, semen thawing was done at 37degree C for 30 seconds. Post thaw progressive motility, plasma membrane integrity and acrosome integrity of spermatozoa frozen in 0.5% BSA was significantly better from 1.0% BSA (P less than 0.05), however these parameters did not differ between control and semen containing 1.0% BSA. Post thaw progressive motility and plasma membrane integrity did not differ between control and semen with 0.5% BSA, however, acrosome integrity of spermatozoa frozen in 0.5% BSA was significantly better than that in control semen (P less than 0.05). As semen frozen in 0.5% BSA showed better post thaw quality, it was compared for in vivo fertility by inseminating 46 buffaloes (23 each with control and semen containing 0.5% BSA). Conception rate did not differ significantly between two treatments although it was higher in the group inseminated with semen containing 0.5% BSA (78%) than that with control semen (56%) (P = 0.12). Superiority of extender containing 0.5% BSA at least in terms of sperm acrosome integrity, and a trend for a higher in vivo fertility are two plus points advocating use of 0.5% BSA in buffalo semen extender and then testing in a large scale fertility trial.