These lipid mediators are currently the focus of considerable interest, for they are also key messengers for cellular homeostasis, inflammation, platelet aggregation, and vascularization. Oxylipins are produced via enzymatic or nonenzymatic oxygenation of both omega-6 and omega-3 PUFAs. Three major enzymatic pathways are involved in their generation: cyclooxygenase, lipoxygenase and cytochrome P450. These pathways are important drug targets for various diseases. The ability to control such pathways with dietary interventions could offset many of the side effects linked to pharmacological treatments. Our study indicated that the availability of unesterified omega-3 PUFA precursors correlated with the increase in the levels of the corresponding omega-3 oxylipins while decreasing the omega-6 oxylipins. Notably, the most abundant oxylipins alterations in fat-1 mice were related to the metabolism of the CYP450 pathway. The CYP450 family of enzymes can produce epoxides from PUFAs, which are subsequently metabolized by the soluble epoxide hydrolase to the corresponding vicinal diols, dihydroxyeicosatrienoic acids. In human and animal studies, the CYP-dependent metabolite profiles were generally reflective of the PUFA composition, suggesting that most of the CYP-epoxygenases accept omega-3s and omega-6s as equally efficient substrates. Recent evidence shows that DHA intake increases the levels of the EPA-derived vicinal diol 17,18-DiHETE metabolized in the CYP/sEH pathway in plasma from piglets, suggesting that DHA retroconversion to EPA may occur to some extent. Although the physiologic properties of AA-derived metabolites of CYP have been studied extensively, the study of DHA and EPA-derived metabolites of CYP450 and their physiologic properties has only recently begun. Omega-3 CYP-metabolites have been described as possessing anti-inflammatory and analgesic properties, as inhibitors of platelet aggregation, and as pulmonary, smooth-muscle relaxants. It has been suggested that some of the beneficial effects of fish-oil-enhanced diets on cardiovascular function may be mediated by the levels of these metabolites. Our results support the hypothesis that CYP-450-mediated omega-3 metabolism might represent a major physiological pathway underlying the reduced disease risk and health benefits observed across numerous fat-1 mouse studies. Finally, the integration of untargeted and targeted lipidomic results provided a detailed molecular signature for a balanced omega-6/omega-3 tissue ratio. Overall, EPA levels were the most remarkable molecular change observed in the plasma of fat-1 mice. Although the use of the fat-1 transgenic mouse model allowed us to eliminate confounding factors of the diet, further work would be needed to establish the validity of these molecular changes in humans.