Omega-3 Phospholipids from Krill Oil Enhance Intestinal Fatty Acid Oxidation More Effectively than Omega-3 Triacylglycerols in High-Fat Diet-Fed Obese Mice

Antisteatotic effects of omega-3 fatty acids (Omega-3) in obese rodents seem to vary depending on the lipid form of their administration. Whether these effects could reflect changes in intestinal metabolism is unknown. Here, we compare Omega-3-containing phospholipids (krill oil; omega 3PL-H) and triacylglycerols (omega 3TG) in terms of their effects on morphology, gene expression and fatty acid (FA) oxidation in the small intestine. Male C57BL/6N mice were fed for 8 weeks with a high-fat diet (HFD) alone or supplemented with 30 mg/g diet of omega 3TG or omega 3PL-H. Omega-3 index, reflecting the bioavailability of Omega-3, reached 12.5% and 7.5% in the omega 3PL-H and omega 3TG groups, respectively. Compared to HFD mice, omega 3PL-H but not omega 3TG animals had lower body weight gain (-40%), mesenteric adipose tissue (-43%), and hepatic lipid content (-64%). The highest number and expression level of regulated intestinal genes was observed in omega 3PL-H mice. The expression of FA omega-oxidation genes was enhanced in both Omega-3-supplemented groups, but gene expression within the FA beta-oxidation pathway and functional palmitate oxidation in the proximal ileum was significantly increased only in omega 3PL-H mice. In conclusion, enhanced intestinal FA oxidation could contribute to the strong antisteatotic effects of Omega-3 when administered as phospholipids to dietary obese mice.