Fish Oil Supplementation Alleviates the Altered Lipid Homeostasis in Blood, Liver, and Adipose Tissues in High-Fat Diet-Fed Rats

Abstract

This study investigated the effects of dietary supplementation of fish oil on the signals of lipid metabolism involved in hepatic cholesterol and triglyceride influx and excretion in high-fat diet (HFD)-fed rats. Fish oil (FO) repressed body (HFD, 533 +/- 18.2 g; HFD+FO, 488 +/- 28.0 g, p < 0.05) and liver weights (HFD, 5.7 +/- 0.6 g/100 g of body weight; HFD+FO, 4.8 +/- 0.4 g/100 g of body weight, p < 0.05) in HFD-fed rats. Fish oil could also improve HFD-induced imbalance of lipid metabolism in blood, liver, and adipose tissues including the significant decreases in plasma and liver total cholesterol (TC) (plasma-HFD, 113 +/- 33.6 mg/dL; HFD+FO, 50.0 +/- 5.95 mg/dL, p < 0.05; liver-HFD, 102 +/- 13.0 mg/dL; HFD+FO, 86.6 +/- 7.81 mg/dL, p < 0.05), blood, liver, and adipose triglyceride (TG) (blood-HFD, 52.5 +/- 20.4 mg/dL; HFD+FO, 29.8 +/- 4.30 mg/dL, p < 0.05; liver-HFD, 56.2 +/- 10.0 mg/dL; HFD+FO, 30.3 +/- 5.28 mg/dL, p < 0.05; adipose-HFD, 614 +/- 73.2 mg/dL; HFD+FO, 409 +/- 334 mg/dL, p < 0.05), and low density (HFD, 79.8 +/- 40.9 mg/dL; HFD+FO, 16.6 +/- 5.47 mg/dL, p < 0.05) and very-low-density (HFD, 49.7 +/- 33.3 mg/dL; HFD+FO, 10.4 +/- 3.45 mg/dL, p < 0.05) lipoprotein and the significant increases in fecal TC (HFD, 12.2 +/- 0.67 mg/dL; HFD+FO, 16.3 +/- 2.04 mg/dL, p < 0.05) and TG (HFD, 2.09 +/- 0.10 mg/dL; HFD+FO, 2.38 +/- 0.22 mg/dL, p < 0.05) and lipoprotein lipase activity of adipose tissues (HFD, 16.6 +/- 3.64 mu M p-nitrophenol; HFD+FO, 24.5 +/- 4.19 mu M p-nitrophenol, p < 0.05). Moreover, fish oil significantly activated the protein expressions of hepatic lipid metabolism regulators (AMPK alpha and PPAR alpha) and significantly regulated the lipid-transport-related signaling molecules (ApoE, MTTP, ApoB, Angptl4, ApoCIII, ACOX1, and SREBPF1) in blood or liver of HFD-fed rats. These results suggest that fish oil supplementation improves HFD-induced imbalance of lipid homeostasis in blood, liver, and adipose tissues in rats.