The effect of glutathione antioxidant addition in maturation medium on the morphology of Garut sheep (Ovis aries) oocytes after vitrification

The study regarding the addition of glutathione antioxidants in the maturation medium in Garut sheep oocytes has been done. The purpose of this study was to evaluate the addition of glutathione antioxidants on oocyte morphology at post-vitrification. A total of 129 oocytes were matured in vitro using TCM-199 medium combined with glutathione antioxidants with a concentration of 0 mM (KK); 0.5 mM (KP1); 1 mM (KP2); and 1.5 mM (KP3). Oocytes were then vitrified using a combination of 15 % ethylene glycol and 15 % dimethyl sulfoxide as cryoprotectants. Oocyte evaluation was carried out after 7 days of storage in liquid nitrogen, including oocyte maturity and oocyte morphology. The percentages of mature oocytes are 53.13 % (0 mM), 55.88 % (0.5 mM), 59.38 % (1 mM), and 67.74 % (1.5 mM) and the percentages of normal oocytes are 56.25 % (0 mM), 64.71 % (0.5 mM), 71.88 % (1 mM) and 87.10 % (1.5 mM). The results of ANOVA tests showed that the data were not significantly different between groups (P > 0.05), but the percentage tends to increase with the increase of antioxidants concentration. The addition of glutathione antioxidants in the maturation medium seems to help maintain oocyte morphology until post-vitrification, although not significant.