Effect of Carnitine on Hariana Bull Spermatozoa Function After Cryopreservation

BACKGROUND: Carnitine reduces reactive oxygen species-induced apoptosis and DNA fragmentation through its antioxidant effect. OBJECTIVE: To investigate the effect of carnitine on capacitation, mitochondrial activity, acrosomal integrity, reactive oxygen species (ROS), membrane fluidity, and DNA fragmentation during the cryopreservation of Hariana bull spermatozoa. MATERIALS AND METHODS: Thirty-two semen ejaculates were obtained using artificial vagina (AV) from four seemingly healthy Hariana bulls. Following dilution, the diluted semen samples were split into four aliquots: Group I, the control, included no carnitine; Groups II, III, and IV were the aliquots that contained carnitine supplements of 2.5, 5, and 10 mM, respectively. These four diluted semen samples were then processed immediately for freezing and equilibration. RESULTS: Regarding post-thaw sperm parameters, such as viability, motility, velocity parameters, capacitation status, mitochondrial activity, acrosomal integrity, reactive oxygen species (ROS), membrane fluidity, and DNA fragmentation, Groups II and III, containing 2.5 mM and 5 mM carnitine respectively, had significantly (P<0.05) improved parameters compared to the Group I (control). At 5 mM, there was a substantial (P<0.05) decrease in early apoptotic-like alterations in sperm cells, accompanied by a greater population of sperm cells with high mitochondrial membrane potential. CONCLUSION: Carnitine has been shown to have cryoprotective properties in semen extenders. For improved postthaw sperm quality, carnitine may be added to a Hariana bull semen extender at a dose of 5 mM.