Avaliação In vitro do sêmen caprino criopreservado em diluente acrescido de superóxido dismutase e catalase em diferentes concentrações

Abstract

With the objective of to evaluate mitochondrial membrane potential (MMP), kinetic, the structural and ultrastructural of goat sperm submitted to freezing in skimmed-milk and glycerol, superoxide dismutase and catalase. It was used five bucks of Boer race, submitted to semen collect by artificial vagina. Semen samples were diluted in skimm-milk plus glycerol (7%), aiming have 320x106 sperm/mL, supplemented with antioxidants according to the experimental groups: G1) extender (control), G2) extender SOD + 25 IU/mL; G3) extender + SOD 50 IU/mL; G4) extender + SOD 100 IU/mL; G5) extender + CAT 25 IU/mL; G6) extender + CAT 50 IU/mL; G7) extender + CAT 100 IU/mL and G8) extender + SOD 100 IU/mL + CAT 25 IU/mL. Then the samples were packed in straws (0.25 mL), frozen and stored in cold storage cylinder (-196 oC). After thawing (37 ºC/30 seconds), aliquots of semen frozen/thawed of each group were evaluated to PMM, kinetic (CASA), structure and ultrastructure of spermatozoa, where did not observe significant difference (P>0.05) among experimental groups in parameters PMM, kinetic, iMP and iAc. In ultrastructural evaluation, fresh sperm was morphologically preserved mainly on mitochondrial membrane. Analyzes of thawed cells showed greater quantity of damages on acrosome; however, in lower percentage on G8 cells. G7 cells showed ultrastructural damages in acrosomes of 92.31%ofspermatozoas. In contrast, great percentage of spermatozoa have plasma and acrossomal membranes intacts, mainly on G2, G4 and G8 groups. Based on the ultrastructural results, it can be recommended addition of SOD (100 U/mL) and CAT (25 U/mL) on the freezing goat semen diluents with skimmed-milk and glycerol; as well as other studies should be realized using higher concentrations than 100U/mL of SOD in this diluent to freezing goat semen, associated to in vivo evaluation of these antioxidant action.