L-Cysteine improves bovine oocyte developmental competence in vitro via activation of oocyte-derived growth factors BMP-15 and GDF-9.

This study was designed to investigate the effect of different concentrations of L-cysteine supplementation into the maturation medium on the oocyte nuclear maturation, cumulus cell expansion, ultrastructure of the oocytes and the expression of oocyte-derived growth factors BMP-15, GDF-9 and CB-1 genes. Cumulus oocyte complexes (COCs) were collected from cow's ovaries obtained from abattoir and incubated at 38.5°C in maturation media supplemented with 0, 0.