Effect of sperm concentration on characteristics and fertilization capacity of rooster sperm frozen in the presence of the antioxidants catalase and vitamin E

The objective of this study conducted was to determine the influence of different levels of sperm concentration, including catalase (CAT) and vitamin E (VitE) in rooster semen extender on postthawed quality and fertility of rooster semen. Semen was collected twice a week from six roosters (Arian) and diluted according to experimental treatments consisting of sperm suspensions containing different sperm concentrations (200, 400, and 600 × 106 sperm/mL) without antioxidant supplementation as control (Con) groups (Con200, Con400, and Con600, respectively), sperm suspensions containing different sperm concentrations (200, 400, and 600 × 106 sperm/mL) supplemented with 5-μg/mL VitE (VitE200, VitE400, and VitE600, respectively) and different sperm concentrations (200, 400, and 600 × 106 sperm/mL) supplementation with 100 IU/mL CAT (CAT200, CAT400, and CAT600, respectively). After thawing; sperm motility, membrane integrity, and mitochondrial function were assessed. Fertility and hatchability rates were determined by using 100 artificially inseminated hens. The percentage of total motility (TM) and activity of mitochondria decreased (P < 0.05) as the sperm concentration increased in control groups. So, the lowest percentage of the TM and activity of mitochondria were observed in the Con600 as compared with other treatment groups. Extenders containing 100 IU/mL CAT and 5-μg/mL VitE resulted in higher (P < 0.05) TM, progressive motility, membrane integrity, and activity of mitochondria compared with control groups. Adding VitE and CAT in different sperm concentrations, the percentage of TM, membrane integrity, and activity of mitochondria decreased (P < 0.05) as the sperm concentration decreased. The highest (P < 0.05) membrane integrity, TM, and progressive motility were recorded at VitE400 and CAT400. Including VitE and CAT in rooster extender with different level sperm concentrations had no effect (P > 0.05) on fertility and hatchability rates. In conclusion, although adding VitE and CAT in extender with different levels of sperm concentration improved postthawed quality of rooster semen, but adding VitE and CAT in the extender have no effect on fertility rate.