Dietary Krill Oil Supplementation Reduces Hepatic Steatosis, Glycemia, and Hypercholesterolemia in High-Fat-Fed Mice

Krill oil (KO) is rich in n-3 fatty acids that are present in phospholipids rather than in triglycerides. In the present study, we investigated the effects of dietary KO on cardiometabolic risk factors in male C57BL/6 mice fed a high-fat diet. Mice (n = 6−10 per group) were fed for 8 weeks either: (1) a nonpurified chow diet (N); (2) a high-fat semipurified diet containing 21 wt % buttermilk + 0.15 wt % cholesterol (HF); (3) HF supplemented with 1.25 wt % KO (HFKO1.25); (4) HF with 2.5 wt % KO (HFKO2.5); or (5) HF with 5 wt % KO (HFKO5.0). Dietary KO supplementation caused a significant reduction in liver wt (i.e., hepatomegaly) and total liver fat (i.e., hepatic steatosis), due to a dose-dependent reduction in hepatic triglyceride (mean ± SEM: 35 ± 6, 47 ± 4, and 51 ± 5% for HFKO1.25, -2.5, and -5.0 vs HF, respectively, P < 0.001) and cholesterol (55 ± 5, 66 ± 3, and 71 ± 3%, P < 0.001). Serum cholesterol levels were reduced by 20 ± 3, 29 ± 4, and 29 ± 5%, and blood glucose was reduced by 36 ± 5, 34 ± 6, and 42 ± 6%, respectively. Serum adiponectin was increased in KO-fed animals (HF vs HFKO5.0: 5.0 ± 0.2 vs 7.5 ± 0.6 μg/mL, P < 0.01). These results demonstrate that dietary KO is effective in improving metabolic parameters in mice fed a high-fat diet, suggesting that KO may be of therapeutic value in patients with the metabolic syndrome and/or nonalcoholic fatty liver disease.