Abstract: Objective: To investigate the effects of fish collagen peptides (FCPs) on hepatic lipid metabolism and redox status in mice fed with a high-fat diet (HFD). Methods: Male C57BL/6 mice (4 weeks old) were randomly divided into three groups (18 animals per group) based on body mass: including control normal diet (CON), high-fat diet (HF) and high-fat diet with 1% added FCPs (PHF) groups. Body mass was recorded on a weekly basis. The animals in each group were randomly assigned according to body mass into two groups which were sacrificed at the end of the 11th and 22th week, respectively. Average daily feed intake (ADFI) and apparent fat digestibility (AFD) were determined. Hepatic triglyceride (TG), total cholesterol (TC) and free fatty acid (FFA) were examined. The mRNA expression levels of key regulators of hepatic lipid metabolism such as acety1 CoA-carboxylase 1 (ACC-1), fatty acid synthase (FAS), sterol regulatory element-binding protein 1c (SREBP1c), cholesterol 7α-hydroxylase 1 (CYP7A1), peroxisome proliferator activated receptor α (PPARα) and carnitine palmity1 transferase 1 (CPT1) were analyzed by quantitative real-time polymerase chain reaction (qPCR). The levels of hepatic redox status indicators such as reactive oxygen species (ROS), malondialdehyde (MDA), total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-Px) and ratio of reduced to oxidized glutathione (GSH/GSSG) were determined. Results: After 22 weeks, in comparison to the HF group, the PHF group showed significantly increased levels of ADFI, fat and energy intake (P < 0.05). The concentrations of hepatic TG and FFA, and the ratios of adipose vacuoles and infiltration area were markedly decreased in the PHF group (P < 0.05). The mRNA expression of CYP7A1, PPARα and CPT1 in liver was significantly up-regulated in the PHF group (P < 0.05). Meanwhile, FCPs improved the redox status due to markedly decreased hepatic ROS (P < 0.05), and significantly increased T-AOC and GSH-Px (P < 0.05). Conclusion: Dietary intervention with 1% FCP can markedly decrease fat accumulation in liver and regulate liver lipid metabolism by improving hepatic redox status and accelerating lipid catabolism in HFD-fed mice.

Key words: fish collagen peptides (FCPs), high-fat diet (HFD), liver, lipid metabolism, redox status