Catalase and superoxide dismutase supplementation to the diluent for cryopreservation of collared peccary semen

Abstract

We evaluated the effects of supplementation with catalase (CAT) and superoxide dismutase (SOD) antioxidants, isolated or combined, on the freezability of collared peccary sperm. Semen aliquots from ten individuals were diluted in Tris‐yolk with or without the presence of antioxidants CAT (200 or 400 IU/mL) and SOD (150 or 300 IU/mL) alone or in combination (CAT: 200 IU/mL + SOD: 150 IU/mL), and then cryopreserved in liquid nitrogen (−196°C). After 1 week, samples were thawed and evaluated for kinetic parameters, membrane functionality and integrity, mitochondrial activity, chromatin integrity, sperm morphology, sperm cell binding capacity and intracellular oxidative levels. Regardless of the use of antioxidants, the treatments did not differ in any of the evaluated parameters, except for the treatment with 300 IU/mL SOD, which showed the highest percentage of static cells (69.1 ± 4.4%) when compared to the group without antioxidant (51.6 ± 3.3%). In general, all samples maintained around 50% of functional membranes, 40% of intact membranes with mitochondrial activity, more than 99% of cells with condensed chromatin, as well as more than 70% of morphologically normal cells. Regarding the binding capacity, the minimum and maximum values found ranged from 33.8 to 194 spermatozoa bound to the perivitelline membrane. Finally, regardless of the presence of antioxidants, all thawed groups showed similar levels of reactive oxygen species (ROS). In conclusion, supplementation with CAT or SOD antioxidants, at the tested concentrations, does not bring benefits to freezability, and the increase in SOD concentration resulted in negative effects on sperm motility in collared peccary semen.