Taurine in semen extender modulates post-thaw semen quality, sperm kinematics and oxidative stress status in mithun (Bos frontalis) spermatozoa

Objective: To assess the effect of taurine on post-thaw semen quality parameters, sperm kinematics, antioxidant and oxidative stress profiles and sperm cholesterol efflux in mithun (Bos frontalis). Methods: A total of 50 ejaculates (n=25 samples) were selected based on biophysical parameters. Each sample was split into four equal aliquots after dilution with the Tris-citrate-glycerol extender. Group I, II, III and IV contained 0 mM (the control), 25 mM, 50 mM and 100 mM of taurine, respectively. Frozen-thawed samples were analysed for motility parameters (progressive forward and in bovine cervical mucus penetration test), kinetic and velocity parameters by computer-assisted sperm analyzer, viability, sperm and nuclear abnormalities, acrosome integrity, plasma membrane and nuclear integrities, sperm enzymatic leakage and biochemical (sperm cholesterol and oxidative stress) profiles. Results: The extender containing 50 mM taurine led to a significant enhancement in viability, acrosomal integrity, plasma membrane integrity, motility (progressive and in cervical mucus), and sperm cholesterol content and notably reduced sperm morphological and nuclear abnormalities, and leakage of intracellular enzymes compared to other taurine treated and untreated control groups (P<0.05). Moreover, in addition to significant improvement in kinetic and velocity profiles, 50 mM taurine protected the integrity of acrosome and biochemical membranes than in the untreated control and other taurine treated groups. Inclusion of 50 mM taurine held a clear advantage over the control or 25 mM or 100 mM taurine in cryopreservation of mithun semen. Conclusions: Taurine (50 mM) supplementation in semen extender can be effectively utilized to reduce oxidative stress and improve post-thaw semen quality in mithun.