Espermatozoides caprinos criopreservados em meio à base de leite desnatado acrescido de glutationa reduzida

Abstract

Aiming to evaluate in vitro effect of different concentrations of glutathione reduced (GSH) in skimmedmilk and glycerol 7% it was used semen from five Boer bucks. After collect and evaluation, a pool of samples was diluted in skimmed-milk and glycerol 7% plus antioxidant: G1) Control; G2) GSH 2mM mL -1; G3) GSH 5mM mL -1 and G4) GSH 7mM mL -1. Samples were frozen in straws (0.25mL) and stored at- 196 oC. After thawing, samples were subjected to integrity of the plasma membrane (iMP) and acrosomal (iAc), mitochondrial membrane potential (MMP), kinematic and ultrastructure analysis. Control and GSH (2, 5 and 7mM mL -1) groups did no differ (P>0.05) in iMP, iAc, PMM and kinematic parameters. In the ultra structural analysis, percentages of acrosome and plasma membrane (tail and head region) intact did not differ (P>0.05) between groups. However, Controlgroup had higher percentage (P<0.05) of gametes with intact axonemes than those of GSH (2, 5 and 7mM mL -1) groups. Higher percentage (P<0.05) of sperms with intact mitochondrias were observed on Control group than those of GSH (5 and 7mM mL -1). It can be concluded that the GSH (2, 5 and 7mM mL -1) addition in skimmed-milk diluent to freeze goat semen did not preserve sperm integrity.