The effect of melatonin on kinetic parameters of Awassi ram sperm during cooling at +4°C using the sperm analysis system (CASA)

Abstract

This study was conducted to test the effect of adding melatonin as an antioxidant to the semen dilution medium of Awassi rams. Semen was collected from five rams using the electroejaculation method. The samples were transported directly to the laboratory, and melatonin was added to Tris Egg yolk diluent in different concentrations {0.5(M1), 1(M2), 1.5(M3)} mM, and stored at +4°C for 72 hours. Kinetic parameters were evaluated using the CASA system after (24, 48,72) hours. The results showed that all treatments significantly (P<0.001) outperformed the control (M0) in the progressive motility, total motility, and rapid motility. The average percentages of progressive motility of sperm for treatments M1, M2, M3, and M0 were (53.03, 66.90, 64.63, and 44.85%), respectively. Treatment M2 significantly outperformed the control and other treatments (P<0.001) in sperm velocity parameters: VCL (curved velocity), VSL (linear velocity), and VAP (average path velocity). The mean sperm velocity for curvilinear velocity for treatments M1, M2, M3, and the control were (76.05, 88.38, 84.64, and 68.58 microns/s), respectively. It has been shown that adding melatonin as an antioxidant to the semen diluent of rams contributed to maintaining sperm quality during cooling at +4°C. Given that the 1 mM concentration outperformed all parameters, we recommend adding melatonin at a 1 mM.