| Dissertation note |
It is well recognized that cryopreservation of bovine semen results in decreased spermatozoal viability due to cryodamages. Oxidative stress is produced due to Reactive Oxygen Species (ROS) during freez-thaw process.Extreme production of ROS during cryopreservation has been associated with decreased post thaw %age motility, viability, and membrane integrity and sperm fertility capability. Basically antioxidants works to reduce or, taking up the formation of ROS. In recent years, taurine has been used as anti-oxidant in semen extenders and has been used in the cryopreservation of sperm from many species to improve post-thaw quality of spermatozoa by inhibiting lipid peroxidation and protecting cells against accumulation of ROS. Therefore, supplementation of taurine in semen extendercontaining 0,15,30,45 and 60mM concentration was used to decrease the harmful effects of cryopreservation on Sahiwal bull spermatozoa. Three Sahiwal bulls (4-8years) were used in the present study. The bulls were maintained at Semen production unit, Qadirabad and were offered good quality seasonal fodder (at the rate of 10% body weight), supplemented with concentrates (2-4kg/day). The semen was collected from each bull twice a week. Initially the semen was assessed for volume, motility, and concentration. Then the semen was pooled from all bulls and divided into 5 aliquots (150 ul each). Each aliquots diluted with 5groups extender which contain 0, 15, 30, 45 and 60mM taurine concentration. The semen was filled in 0.5ml straws cooled to 5c for 4 h, then frozen and stored in liquid nitrogen (-196c). Post-thaw motility, viability, plasma membrane integrity, acrosome and DNA integrity was evaluated and statistically analyzed by one way ANOVA. The group supplemented with 60mM concentration of taurine decreased all parameters of post thaw quality ofSahiwal bull spermatozoa. However the group supplemented with 15mM concentration of taurine show higher significantly (p<0.05) results than control and other groups. The post-thaw motility of the group supplemented with 15mM taurine concentration (54.50±2.1) higher significantly (p<0.05) than control (45.50±0.90) and other groups. The treatment group of 15mM taurine concentration show signifantly (p<0.05) higher viability (58.60±1.58 vs50.80±0.70) , plasma membrane integrity (57.10±1.43 vs 49.00±0.65) acrosome integrity (56.80±0.59 vs48.10±1.66) and DNA integrity (98.80±0.23 vs 97.54±0.39) as compared to the control and other groups. It is concluded that the maximum beneficial effect of addition 15mM taurine in tris-based egg yolk extender gives better post-thaw parameters. |
