Dietary fish oil and stearate action on adipose lipid metabolism transcriptomics in periparturient dairy goats

The aim of this study was to evaluate the effects of saturated or unsaturated fatty acids on adipose mRNA level of genes involved in the major lipogenic metabolic pathways. Twenty-three second parity alpine dairy goats were assigned to three treatments: (C; n=8) fed a non fat-supplemented basal diet, (ST; n=7) fed a basal diet supplemented with stearic acid and (FO; n=8) fed a basal diet supplemented with fish oil. The supplementation started from the last week of gestation and lasted 21 days after kidding. Treatments supplied 30g/head/d extra fatty acids during the dry period and 50g/head/d during lactation. Individual blood samples were taken at 14, 7 and 2 days before the expected kidding day as well as 0, 2, 7, 14 and 21 DIM. Liver and adipose tissue biopsies from each experimental subject were harvested on days -7, +7 and +21 relative to parturition. Quantitative real-time RTPCR of ADIPOQ, LPIN1, LPL, PPARG, SREBF1 and THRSP expression was performed. Data obtained were analyzed using the MIXED procedure of SAS. No differences were observed for milk production, milk composition, body weight and body condition score. Differences were detected for EB between C compared with ST and FO at day 7 (0.34 vs. -1.12 and 0.91 respectively; P≤0.05). Serum cholesterol concentration was significantly higher in FO compared to C (P<0.01) and ST (P<0.05) at day 21. Fat supplementation significantly affected subcutaneous adipose genes involved in TAG synthesis (LPIN1), in the regulation of lipogenesis (THRSP) and nuclear receptor (SREBF1). No effects were observed for genes involved in LCFA uptake (LPL) and on the expression of the adiponectin (ADIPOQ). LPIN1 expression was significantly higher in the FO group compared with ST (1.46-fold vs. 0.59-fold; P<0.04) suggesting increased lipogenesis. THRSP (P=0.003) and SREBF1 (P=0.04) were up regulated before kidding and increasingly down regulated from 7 to 21 days postpartum. In conclusion, this study highlighted the important role of saturated or unsaturated fat administration in dairy goat diets to modulate mRNA expression of genes involved in TAG synthesis, regulation of lipogenesis and nuclear receptor.