Effect of L-Ascorbic acid on in-vitro maturation of vitrified-Thawed bovine oocytes

The present study was conducted to assess the effect of supplementation of L-ascorbic acid (vitamin C) on in-vitro maturation (IVM) of vitrified-thawed bovine oocytes. A total of 264 normal vitrified-thawed bovine follicular oocytes were divided into four experimental groups consisting of 66 oocytes in each group. In-vitro maturation was done in the medium supplemented with different concentrations of vitamin C @ 50 μM, 100 μM and 200 μM. In the control group, in-vitro maturation was done in medium without addition of vitamin C. In-vitro maturation was conducted for 24 hrs at 38.5oC in presence of 5% CO2 in a CO2 incubator. The mean percentages of vitrified oocytes in medium supplemented with 50 μM, 100 μM and 200 μM vitamin C were found to be 52.79 ± 1.39 and 33.56 ± 2.18,71.19 ± 2.63 and 54.57 ± 1.69and 51.17 ± 3.59 and 30.43 ± 2.01, respectively in respect of cumulus cell expansion and polar body formation. The percentage of both cumulus cell expansion and polar body formation in medium supplemented with 100 μM vitamin C was found to be significantly higher (P<0.01) than that of the 50 μM and 200 μM vitamin C supplemented groups. The mean percentages of cumulus cell expansion and polar body formation in the vitrified control group were 51.67 ± 1.94 and 30.26 ± 0.16, respectively. Hence, it could be concluded that in-vitro maturation in medium supplemented with 100 μM vitamin C enhances the growth of vitrified-thawed bovine oocytes.