In vitro development of ovine oocytes cultured in the presence of GDF9 at chemically defined or undefined maturation medium

The major factor that affects oocyte developmental competency is regulation of oocyte in vitro maturation (IVM). According to the literature, oocyte-secreted and exogenous growth differentiation factor 9 (GDF9) have little influence on ovine in vitro maturation. This result may have been masked by the presence of serum or other additive in the maturation medium. Thus, we aimed to compare the developmental competency of ovine oocyte cultured in the presence of GDF9 at chemically defined or undefined maturation medium. Abattoir-derived ovine ovaries were transported to the laboratory in saline. After aspiration of follicles, good qualities cumulus oocyte complexes (COCs) were cultured with and without serum in the presence of exogenous and endogenous GDF9. Then, morphological cumulus cell expansion, cleavage rate and blastocyst yield were evaluated between experimental groups. In general, the use of chemically defined maturation media leads to significantly lower cumulus expansion. Cumulus expansion index in the presence of endogenous GDF9 and serum was lower than its control whereas in the absence of serum, exogenous and endogenous GDF9 had little influence on cumulus expansion. In the presence of exogenous GDF9 and absence of serum, cleavage rate was lower than exogenous and endogenous GDF9 in the presence of serum. Blastocyst rates showed no statistically significant difference between groups. Factorial analysis of the effect of GDF9, serum and their interactions on cleavage and blastocyst rates revealed no statistically significant difference between groups. This study provides evidence that GDF9 was not predominant factor in ovine cumulus expansion and oocyte development. Moreover, our results suggest that GDF9 under certain conditions might have interacted with serum born factors. (C) 2014 Elsevier B.V. All rights reserved.