Conjugated linoleic acid supplementation: Insights into prostaglandin synthesis and in vitro embryonic development

Modulation of prostaglandin synthesis, specifically, decreasing prostaglandin F_2α (PGF_2α) and increasing prostaglandin E₂ (PGE₂) and interferon-tau (IFNT), can support maternal recognition of pregnancy (MRP) in cattle. Conjugated linoleic acid (CLA) is known to influence prostaglandins (PG) synthesis in cell cultures; however, its effect on in vitro-cultured bovine oocytes and embryos remain unclear. We hypothesized that CLA supplementation in oocytes and embryo culture media would reduce PGF_2α synthesis, increases PGE₂ synthesis and PGE₂:PGF_2α ratio in embryos, modulate the expression of genes involved in PG and IFNT synthesis, and enhance embryo development. This study aimed to evaluate the effects of different CLA (a mixture of cis- and trans-9,11- and -10,12-octadecadienoic acids) concentrations (50-150 μM) added during in vitro maturation (IVM) and/or in vitro culture (IVC) on in vitro embryo production, PGE₂ and PGF_2α synthesis, and the expression of genes related to PG synthesis (AKR1B1, PTGS2, PTGES) and MPR (IFNT) in embryos. Oocytes and embryos were treated with CLA (50, 100, and 150 μM) during IVM or during both IVM and IVC. PGE₂ and PGF_2α concentrations were quantified by ELISA, and transcript abundance in embryos at the end of IVC was assessed by qPCR. CLA supplementation at all tested concentrations during IVM and/or IVC reduced both PGE₂ and PGF_2α synthesis in embryos, without affecting the PGE₂:PGF_2α ratio, or the relative expression of the evaluated genes. These findings suggest that CLA modulates PG synthesis in bovine embryos and underscore the importance of PG regulation for the successful establishment of MRP.