Estrogen Promotes Hepatic Synthesis of Long-Chain Polyunsaturated Fatty Acids by Regulating ELOVL5 at Post-Transcriptional Level in Laying Hens.

The very long chain fatty acid elongase (ELOVL) plays an important role in the synthesis of long-chain polyunsaturated fatty acids (LCPUFA). Previous studies suggest that chicken could be an alternate source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In this study, we detected that , which plays a key role in the biosynthesis of omega-3 (-3) and omega-6 (-6) polyunsaturated fatty acids (PUFA), was highly expressed in the liver of laying hens and increased rapidly after sexual maturity. Bioinformatic analysis revealed ELOVL fatty acid elongase 5 () gene as a putative target of miR-218-5p, miR-19a-3p, miR-19b-3p, miR-30a-5p, miR-30b-5p, and miR-30e-5p. We demonstrated estrogen downregulated microRNA (miRNA), and that is a direct target of miR-218-5p, which was located in intron 14 of the Slit guidance ligand 2 () gene and co-expressed with the host gene. Overall, estrogen enhanced hepatic synthesis of LCPUFA by functioning as a negative regulator of miRNA thereby augmenting the expression of these miRNA target genes, especially , which plays a key role in the biosynthesis of -3 and -6 LCPUFA. This study provides a novel model for the use of estrogen in the poultry industry as an inducer of expression to enhance hepatic -3 and -6 LCPUFA synthesis at the post-transcriptional level.