ailability of FO and FM seriously limits the growth of aquaculture production and there is an urgent need to find more sustainable alternatives. Vegetable oils can replace FO in salmon feeds without compromising fish growth or condition al though, at high levels of replacement, tissue levels of n 3 LC PUFA are significantly things reduced. The effects of FO replacement by VO are becoming well characterized in the hepatic transcriptome of salmonids, and other species. However, studies on intestinal tran scriptome are few and restricted to effects of replace ment of FM by plant proteins, particularly soybean meal, given its potential to cause enteritis. It is now clear that intestine in salmonids is not simply a site for reacylation and packaging of dietary lipids but it also has important roles in fatty acid metabolism, including LC PUFA biosynthesis.

Furthermore, dietary VO can induce major histological changes in fish enterocytes, originating mostly from supranuclear lipid droplet for mation, possibly due to altered reacylation mechanisms and decreased phospholipid synthesis. In some cases, these accumulations were large enough to be deemed pathological. A recent study investigat ing effects of dietary FO replacement by VO on intes tinal transcriptome in Atlantic cod indicated potential effects on lipid absorption and transport and suggested morphological and structural changes to the intestinal muscle layer. Furthermore, both this and a previous study on Atlantic salmon showed significant effects on expression of genes involved in cell proliferation and apoptosis.

Therefore, there is indication that intes tine may be affected by changes in lipid components of feed formulations. Given its crucial roles in nutrient ab sorption, protection against the entry of pathogens, and immune function, further attention is warranted and impacts of FO replacement require investigation in intestine, particularly in salmon where important changes in diet formulation are already being applied. This study is a large scale analysis of the effects of re placement of dietary FO by VO on the transcriptome and proteome of Atlantic salmon intestine. Furthermore, given recent interest in evaluating genetic selection as a feasible strategy, in conjunction with changes in com mercial feed formulation, to meet worldwide demand for farmed fish without compromising animal welfare or nu tritional value, two groups of Atlantic salmon families, Lean and Fat, were studied to examine the po tential effects of genetic background.

This experiment was performed in parallel with another microarray study looking at effects in the hepatic transcriptome, analysing samples from the same individuals, enabling a glo bal and comprehensive assessment of the physiological and molecular effects of FO replacement by VO in At lantic salmon, including potential interactions Carfilzomib with genotype. Results Microarray analysis find FAQ Two way ANOVA of the cDNA array dataset returned 1409, 1626 and 862 significant genes fo