Are the optimum levels of the catalase and vitamin E in rooster semen extender after freezing-thawing influenced by sperm concentration?

To date, there has no report to evaluate the interaction effects of antioxidant and sperm concentration in rooster semen cryopreservation. This study was aimed to investigate the effects of vitamin E (VitE) and catalase (CAT) at different sperm concentrations on the rooster post-thawed sperm quality. Semen samples were collected twice a week from ten roosters (ROS 308) and diluted according to experimental treatments. The treatments consist of different sperm concentrations (200, 400 and 600 × 106 sperm/mL) with supplementation VitE (5 μg/mL; VitE200, VitE400, and VitE600, respectively) or CAT (100 IU/mL; CAT200, CAT400, CAT600, respectively) and without antioxidants [Control (Con); Con200, Con400, Con600, respectively]. After thawing, motion characteristics were assessed using a CASA system. Plasma membrane integrity and malondialdehyde (MDA) level were evaluated with Hypoosmotic swelling test (HOST) and Thiobarbituric acid (TBA), respectively. The higher percentage of total motility, progressive motility, viability and membrane integrity were obtained in VitE400 (81.16 ± 1.21, 18.44 ± 1.19, 85.47 ± 1.07, 86.91 ± 1.16, respectively) and CAT400 (79.38 ± 1.21, 17.19 ± 1.19, 83.42 ± 1.07, 85.73 ± 1.16, respectively) compared to control groups. Moreover, the lowest percentage of MDA was measured in VitE400, VitE600 and CAT400 rather than other groups (1.489, 1.500, 1.510 ± 0.06, respectively). In conclusion, the results of the present study demonstrate that VitE (5 μg/mL) and CAT (100 IU/mL) independently at sperm concentration, 400 million sperm/mL could beneficial effect for preservation of rooster semen during cryopreservation.