P-136: In Vitro Development of Ovine Oocytes Matured in A Chemically Defined Medium

Background: Despite great advances achieved in the field of in vitro oocyte maturation (IVM), almost all IVM media are supplemented with undefined component which not only pose the risk of pathogen transmission but also hinders our knowledge of molecular mechanisms of maturation. One of these components is serum that containing various concentration of unknown molecules affecting cellular processes, therefore the use of serum needs to be studied. We aimed at comparing developmental competency of ovine oocyte grown with and without serum. Materials and Methods: Abattoir-derived ovaries were transported to the laboratory in saline. After aspiration of follicles, good quality oocytes were divided into two experiments. In the first experiment oocytes were cultured in defined maturation medium. The second experiment was carried out in undefined maturation medium. Then cleavage rate, blastocyst yield and morphological Cumulus cell expansion were evaluated between two experimental groups. Results: In general, the use of chemically defined maturation media leads to significantly lower cleavage rate and blastocyst yields (91.24 ± 3.06 vs. 78.77 ± 3.66 and 42.65 ± 1.66 vs. 22.02 ± 8.44 respectively). The cumulus expansion index (CEI) of defined maturation group significantly lower than other treatment group. Conclusion: Thus to improve the developmental competence of mammalian oocyte, several common growth factors, hormones and antioxidants have been added to defined maturation media. This purpose needs to more investigation about different defined maturation media.