Effect of PUFA on embryo cryoresistance, gene expression and AMPKalpha phosphorylation in IVF-derived bovine embryos.

ABSTRACT

The objectives of the present study were to evaluate the effect of conjugated linoleic acid (CLA t10, c12, C182), linolenic acid (C183) and docosahexaenoic acid (DHA, C226) supplementation on in vitro bovine embryo development, embryo survival after cryopreservation, gene expression and AMPKalpha phosphorylation. Control groups with modified synthetic oviduct fluid (mSOF)+/-100microM beta-mercaptoethanol (beta-ME) were performed. The effects of co-culture with bovine oviduct epithelial cell (Boec) monolayers, serum supplementation and embryo development in the ewe oviduct, on gene expression were also examined. Experiments 1 and 2 a lower d 7 embryo survival was found with 100microM C226 and 100microM C182 supplementation compared to 1microM C226 and 100microM beta-ME supplementation (P<0.05). C183 supplementation had no effect on d 7 embryo survival, but 100microM C183 increased d 8 embryo survival compared to 100microM beta-ME supplementation (P<0.05). Experiments 3 and 4 stearoyl-CoA desaturase 1 (SCD1) and sterol regulatory element-binding transcription factor 1 (SREBP1) mRNA decreased after 10microM C226 supplementation compared to all other supplementations (P<0.05). A lower fatty acid desaturase 2 (FADS2) transcript level was found with 100microM C182, 10microM C226 and 10microM C183 supplementations compared to groups without fatty acid supplementation (P<0.05). Acetyl-CoA-carboxylase (ACC), fatty acid synthase (FAS), adipose differentiation-related protein (ADRP), acyl-CoA synthetase long-chain family member 1 (ACSL1), diacylglycerol O-acyltransferase 1 (DGAT1), carnitin palmitoyltransferase-II (CPT-II) mRNAs expression and AMPKalpha phosphorylation were not modified with PUFA supplementation. Experiment 5 SCD1 and FAS mRNA decrease in Boec group compared to serum supplementation, as SCD1 mRNA in ewe oviduct group (P<0.05). In conclusion, this study showed that a PUFA supplementation with C182, C183 or C226 in bovine culture development for 6 days and co-culture with Boec down-regulate mRNA expression of proteins involved in lipid metabolism in d 7-8 embryo (SCD1 and FADS2 desaturases), probably through SREBP1 mRNA regulation after 10microM C226 supplementation, indicating a modification of saturated/unsaturated fatty acid balance in bovine blastocyst.