THE EFFECT OF in Vitro MATURATION OF BOVINE OOCITES WITH FETAL BOVINE SERUM ON THEIR MITOCHONDRIAL ACTIVITY FOLLOWING DEVITRIFICATION

Objective. To evaluate the effect of in vitro maturation (IVM) with fetal calf serum (FCS) on the mitochondrial activity (membrane potential) of devitrified bovine oocytes. Materials and methods. Bovine oocytes were collected from post-mortem ovaries and matured in vitro in SOFaa medium with and without FCS. The oocytes were cryopreserved by OPS vitrification. Devitrified oocytes were evaluated for their mitochondrial membrane potential by JC-1 dye staining. Statistical evaluations were done using Student’s t-test and analysis of variance. Results. There was a statistically significant difference (p<0.05) between IVM treatments for the mitochondrial membrane potential levels of devitrified oocytes, with averages of 39.8 ± 2.38% and 50.3 ± 2.59% for MIV with and without serum, respectively. There was no IVM with serum effect over the distribution of high mitochondrial membrane potential; nevertheless there was a statistically significant difference (p<0.05) in this parameter between fresh and devitrified oocytes. Conclusions. FCS in the IVM has a deleterious effect on mitochondrial membrane potential after cryopreservation and cryopreservation alters the proportions of distribution patterns of high activity mitochondria in in vitro matured bovine oocytes.