The effect of the addition of melatonin (Mt) on the maturation and / or vitrification of bovine oocytes on cleavage and subsequent embryonic development was evaluated. Oocyte-cumulus cell complexes (COCs) were obtained from creole cows by ovum pick up (OPU) and by follicular aspiration from abattoir ovaries (AO). From the pool of oocytes obtained from both sources, those with homogenous cytoplasm and three or more compact layers of cluster cells were selected. The selected COCs were randomly assigned to five treatments: T1, matured with Mt and vitrified without Mt; T2, matured and vitrified with Mt; T3, matured without Mt and vitrified with Mt; T4 (control) matured and vitrified without Mt; T5, matured without Mt and not vitrified. The concentration of Mt in the maturation and vitrification media was 0.01 μM (10-9 M). The oocytes were matured, vitrified, fertilized and the presumed zygo...

The effect of the addition of melatonin (Mt) on the maturation and / or vitrification of bovine oocytes on cleavage and subsequent embryonic development was evaluated. Oocyte-cumulus cell complexes (COCs) were obtained from creole cows by ovum pick up (OPU) and by follicular aspiration from abattoir ovaries (AO). From the pool of oocytes obtained from both sources, those with homogenous cytoplasm and three or more compact layers of cluster cells were selected. The selected COCs were randomly assigned to five treatments: T1, matured with Mt and vitrified without Mt; T2, matured and vitrified with Mt; T3, matured without Mt and vitrified with Mt; T4 (control) matured and vitrified without Mt; T5, matured without Mt and not vitrified. The concentration of Mt in the maturation and vitrification media was 0.01 μM (10-9 M). The oocytes were matured, vitrified, fertilized and the presumed zygo...