POSSIBILITY OF USING THE BOVINE SEMINAL PLASMA AS A DILUENT FOR CRYOPRESERVATION OF EGYPTIAN BUFFALO SEMEN

The seminal plasma separated from ejaculates of the same or different animal species has been used as an extender for semen preservation to minimize the negative effects of reduced temperatures and cryo-damage on mammalian spermatozoa. The semen of sexually-matured buffalo bulls (n=5) collected at 3-4 day-interval by artificial vagina was used in this study for a duration of 12 weeks. Spermatozoal mass motility was at least 70%. Semen was collected, pooled, diluted with bovine seminal plasma (BSP) (after adding egg-yolk, glycerin and anti-biotics) or Tris-extender at 3 dilution rates (1:10, 1:15 and 1:20), equilibrated at cool temperature (4-5C) for 2 h, frozen for one month at -196C (liquid nitrogen), and thawed at 37C for 15 s. Semen was evaluated for the percentages of progressive motility (PM), live sperm (LS), sperm abnormalities (SA), acrosome damage (AD), and membrane integrity (MI) in diluted, equilibrated and thawed cases, besides the head to head agglutination (HHA) percentage post-thawing. In the sperm medium of thawed semen, AST, ALT, LDH activities and total antioxidant activity (TAA) levels were also determined. Sperm fertilizability was recorded based on the best results for BSP or Tris-extender. Results showed that freezability parameters (PM, LS, SA, AD, MI and HHA percentages), the activity of AST, ALT and LDH, and TAA and conception rate were improved (P<0.05) for thawed buffalo semen diluted with BSP at a rate of 1:20 in comparison with Tris-extender at 1:10. The bovine seminal plasma of excluded ejaculates for poor quality could be considered as a promising successful extender for cryopreserved buffalo semen.