The in vitro investigation of lycopene effects on post-thawed ram sperm
This study was conducted to evaluate the effects of lycopene on quality parameters of cryopreserved ram semen. Semen samples were collected from three Santa Inês rams to form a seminal pool (n = 8). Aliquots from each pool were diluted in Tris-egg yolk extender to create experimental groups containing 0 µM (control), 0.1 µM, 1 µM and 5 µM lycopene. The samples were evaluated for sperm kinetics, integrity of plasma and acrosomal membranes, intracellular reactive oxygen species (ROS) production and lipid peroxidation immediately after thawing and after incubation for two hours at 37 °C. The addition of lycopene had no effect on the parameters that were evaluated at the time of thawing when compared with the control. However, after incubation, the groups with added lycopene showed a decrease in progressive motility. All experimental groups showed a significant reduction in linearity and straightness following incubation. Furthermore, the 5 µM lycopene group showed a decrease in wobble and an increase in amplitude of lateral head displacement. In conclusion, the addition of lycopene to the freezing extender of ram semen affected the kinetics parameters of cryopreserved spermatozoa after a two-hour incubation period.
Keywords: carotenoid, flow cytometry, kinetic, sheep