Inclusion of catalase in semen extender modulates the post thaw semen quality and oxidative stress profiles in mithun spermatozoa

Present study was designed to assess the effect of catalase on post-thaw semen quality parameters (SQPs), sperm kinematics, antioxidant and oxidative stress profiles and sperm cholesterol efflux in mithun (Bos frontalis). A total of 25 ejaculates were selected based on biophysical parameters and each sample was split into four equal aliquots and diluted (to get final concentration of 60 million spermatozoa per mL) with the TCG extender containing either 0 U/mL, 50 U/mL, 100 U/mL, and 150 U/mL catalase in the Group I, II, III and IV, respectively. Frozen-thawed samples were analysed for motility parameters (progressive forward and in bovine cervical mucus [BCMPT]), kinetic and velocity parameters by computer-assisted sperm analyser (CASA), viability, sperm morphological and nuclear abnormalities, acrosomal integrity, plasma membrane and nuclear integrities, sperm intra-cellular enzymatic leakage and seminal plasma biochemical (sperm cholesterol and oxidative stress markers) profiles. Study revealed an enhancement in viability, acrosomal integrity, plasma membrane integrity, motility (progressive and in cervical mucus), sperm cholesterol content and reduction in sperm morphological and nuclear abnormalities, leakage of intracellular enzymes in Group III. Moreover, intactness of acrosome and biochemical membranes were protected significantly in addition to significant improvement in kinetic and velocity profiles in extender containing 100 U/ml catalase. Correlation analysis revealed that sperm kinetic parameters, SQPs and antioxidant parameters had significant positive correlation with each other whereas these profiles were negatively correlated with sperm morphological abnormalities, enzymatic leakage and lipid peroxidation in catalase treated sperm. The results clearly indicated that inclusion of 100 U/ml catalase holds a clear advantage over control or 50 U/ml or 150 U/ml catalase in cryopreservation of mithun semen. It can be concluded from the present study that catalase supplementation in semen extender can be effectively utilized to reduce the oxidative stress and to improve the post-thaw semen quality in mithun.