Fatty acid supplementation in transition goats: a transcriptional study related to inflammation

The aim of the trial was to study the expression of genes and miRNA related to inflammation in adipose tissue of periparturient dairy goats supplemented with saturated or unsaturated fatty acids. Twenty-three second-parity alpine dairy goats were either fed calcium stearate (ST, n.7) or fish oil (FO, n.8) and compared to a control group (C, n.8). The dietary treatments lasted from one week before (30 g/head/d total fatty acids) to three weeks after kidding (50 g/head/d total fatty acids) of either ST (26% C16:0, 69.4% C18:0) or FO (10.4% EPA, 7.8% DHA). Adipose tissue samples on day -7 and 7 and 21 from kidding were analyzed for CCL2, IL10, IL18, IL1β, IL6R, SAA3, HP, IL8, RXRA, and TLR4 expression and 99a, 155, 143, 145, 221, 26b, and 378 miRNA expression. RNA was extracted and primers were aligned with available databases using BLASTN at NCBI. A quantitative PCR by SYBR green was used and the relative expression was determined by a 6-point standard curve. Data were analyzed by a MIXED repeated model in SAS 9.3 after normalization with 3 internal reference genes. No diet effect was observed, but there was a time effect for IL10, SAA3, HP, IL8, RXRA (P<0.05) and miR-155 (P=0.02). IL8 and IL10 were upregulated at days 7 and 21 (P<0.05), compared to day -7), as well as miR-221, that plays a role in inflammation and lipolysis, tended to have the same pattern. Furthermore, HP and SAA3 had the highest upregulation at 7 DIM compared to prepartum. In addition, miR-155, which is involved in the infiltration of immune cells, had a similar expression pattern. Obtained data support the existence of an acute-phase response in the first week after kidding in adipose tissue, as observed in cows.