Omega - 3 fatty acids of marine origin exert beneficial effects on lipid metabolism and can protect against insulin resistance in high fat diet (HFD)-fed animals. Simultaneously, recent studies showed that different lipid forms could have numerous consequences regarding the regulation of energy balance, nutrient absorption, and substrate metabolism. Indeed, when omega-3 was provided as triglycerides (TG, i.e. fish oil), it induced dose-dependently the expression of genes involved in lipid metabolism as well as fatty acid oxidation in small intestine of C57BL/6 mice fed various HFDs. As the underlying mechanism(s) explaining the differences in EPA/DHA bioavailability among various lipid forms of Omega-3 is not entirely clear, we performed a mouse study (n=8 per group) using purified HFDs with control HFD based on corn oil (cHF) and part of the lipids were replaced by omega-3 fish lipids in different forms: as either TG (cHF-F), marine phospholipids (PL; Krill oil, given at two different doses Krill-low (Krill-L) and Krill-high (Krill-H)), and as wax esters in the extract from the zooplankton Calanus finmarchicus (Calanus oil CAL-L representing same omega-3 levels as Krill-L diet). As a healthy control we fed a subset of mice standard chow (STD). All mice were fed their diet for 8 weeks and after sacrifice, whole small intestine was isolated, frozen and used for RNA isolation and microarray gene expression analysis using 8x60K Agilent arrays. Results showed that PL-H versus control cHFc induced specifically metabolic lipid pathways, while TG and PL-L mainly affected cytoskeleton regulation.