Effect of diet supplementation with fish oil on the mRNA abundance of genes involved in mammary lipogenesis in lactating ewes

3 páginas, 1 figura.-- Trabajo presentado a las XVI Jornadas sobre Producción Animal AIDA (Zaragoza, 19 al 20 de mayo, 2015).This study was conducted in sheep to investigate the relationship between changes in both the mRNA abundance of genes involved in mammary lipogenesis, and the milk fatty acid (FA) composition, in response to a diet known to induce milk fat depression (MFD). Twelve ewes (6 animals/treatment) received a total mixed ration supplemented with 0 (control) or 17 g of fish-oil/kg DM, for 31 days. Milk FA profile was analysed by gas chromatography on samples collected on days 0, 7 and 30, and candidate gene expression by quantitative reverse transcription-PCR on samples of mammary secretory tissue removed by biopsy on days -13, 8 and 31. As expected, the fish-oil supplemented diet induced MFD and modified milk FA composition. Increases in some putative antilipogenic FA (e.g., trans-10 18:1, trans-10 cis-12 18:2, and trans-9 cis-11 18:2) were accompanied by reductions in the mRNA abundance of ACACA, FASN, SCD1 and SREBF1, which would support that the nutritional regulation of milk FA composition is mediated by transcriptional control mechanisms. Most variations in mRNA abundance were detected on early stages of the feeding period (day 7) and stayed relatively stable until the end of the assay (d 31).Este trabajo ha sido financiado por la Junta de Castilla y León (Proy. CSI023U13). D. Carreño y P. G. Toral disfrutan, respectivamente, de una beca predoctoral FPI del MINECO y de un contrato Juan de la CiervaPeer reviewe