Effects of EPA on bovine oocytes matured in vitro with antioxidants: Impact on the lipid content of oocytes and early embryo development.

The eicosapentaenoic acid (EPA) is an n-3 polyunsaturated fatty acid (PUFA) present in the lipid composition of bovine oocytes. Little is known about the importance of EPA in bovine oocyte maturation and embryo development in vitro. Although previous work suggest that n-3 PUFAs may inhibit oocyte maturation, the available data are inconsistent. In this study, we evaluated the effect of EPA (1, 10, 100 nM) during in vitro maturation (IVM) of bovine oocytes, alone and in combination with vitamin E (VE) or cysteamine (CYS). EPA treatment in IVM decreased oocyte lipid content and affected lipid droplets pattern (P < 0.05). EPA 100 nM reduced oocytes maturation rate (P < 0.05), without affecting cumulus expansion. At the concentrations tested, EPA did not modify embryo development. However, the addition of antioxidants during IVM reduced the levels of reactive oxygen species in the culture system by increasing intracellular glutathione content (P < 0.05). Besides, the combination of EPA with VE or CYS reduced the percentages of MI oocytes after 24 h of IVM (P < 0.05). EPA reduced oocyte lipid content without any detrimental for embryo development.