Digital gene-expression profiling analysis of the fatty liver of Landes geese fed different supplemental oils.

The goose liver is an ideal model for deciphering lipogenesis molecular mechanisms. This study was designed to investigate the effect of different lipid sources on hepatic lipogenesis in overfed geese. Sixty Landes geese were fed ad libitum with no fat (control) or overfed diets containing 2% goose fat (GF) or rapeseed oil (RO) for 20 days. We measured fatty acid composition of the liver at day 20 of overfeeding. We performed a transcriptomic comparison of fatty liver between GF and RO-fed geese to gain insights into the molecular and cellular events mediating lipogenesis activity. The results showed that there was no substantial effect on fatty liver performance between GF- and RO-fed geese. Significant differences in fatty acid composition were detected between GF- and RO-fed geese. Total ω-6 PUFAs increased and saturated fatty acid decreased (P < 0.05) with RO supplementation when compared with GF, but ω-3 PUFAs did not differ between the two diets. Concentrations of C16:1, C18:1, C18:2, C20:2, and C22:1 were higher (P < 0.05) in the fatty liver of RO-fed geese compared to those in the GF group. Analysis of transcriptome sequencing showed that there were 124 up-regulated and 129 down-regulated differentially expressed genes in the fatty liver of RO and GF-fed geese. Many of these genes code for proteins involved in the lipid metabolic process, including bile secretion, adipocytokine signalling pathway, biosynthesis of unsaturated fatty acids, linoleic acid metabolism, fatty acid elongation and fatty acid biosynthesis, and fat digestion and absorption. Moreover, genes involved in lipid-related pathways such as peroxisome, steroid biosynthesis, steroid hormone biosynthesis, retinol metabolism, and apoptosis were altered, suggesting that the fatty liver of goose fed different oils undertakes both an oxidation function and hormone-related metabolic function. In conclusions, these data suggest that RO supplementation reduces liver lipid oxidation and improves lipogenesis. These findings provide new insights into the molecular mechanisms involved in fatty liver formation and provide valuable resources for analysing mechanisms underlying the effects of oils from different sources on the goose fatty liver.