Chlorogenic acid improves health in juvenile largemouth bass (Micropterus salmoides) fed high-fat diets: Involvement of lipid metabolism, antioxidant ability, inflammatory response, and intestinal integrity

High-fat diets (HFD) is widely applied in aquaculture to achieve a protein-saving effect, whereas long-term intake of high-fat feed will negatively affect the health of fish. Chlorogenic acid (CGA) is an effective antioxidant and anti-obesity substance. However, whether CGA can address a series of adverse effects caused by fish's high lipid diet is unclear. Four diets were formulated: a control diet (C) with approximate 11% lipid; HFD with 18% lipid (HF) and HFD supplemented with 300 and 600 mg/kg CGA (HFC1 and HFC2, respectively) and a nine-week feeding trial was conducted of largemouth bass. Here we show that dietary CGA improves health of largemouth bass by regulating expression of gene responsible for lipid metabolism, inflammation, and antioxidant enzymes. We found that dietary CGA decreases total triglyceride (TG) and total cholesterol (TC) in plasma and nonestesterified fatty acid (NEFA) in liver of largemouth bass, and 600 mg/kg CGA increased mRNA expression levels of lipolysis such as hormone sensitive lipase (HSL) and adipose triglyceride lipase (ATGL), and apolipoprotein A1 (APOA1) in the liver. In addition, we found CGA downregulates mRNA expression levels of interleukin 8 (IL-8) and tumor necrosis factor alpha (TNF-α). Furthermore, we found that CGA decreases malondialdehyde (MDA) level of liver of largemouth bass, while increased mRNA expression of superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT). Our results indicate that CGA plays a role in lipid metabolism, inflammation and antioxidant capacity of largemouth bass fed HFD.