Marine-Derived Chitooligosaccharide Attenuates Obesity and Metabolic Syndrome in Bama Pigs Through LXR-Mediated Cholesterol Metabolism and Gut Microbiota Modulation.

Abstract

Chitooligosaccharide (COS) is a marine-derived natural product obtained from shrimp and crab shells. Although its anti-inflammatory and antioxidant activities are documented, its potential effects on obesity and metabolic syndrome remain largely unclear. This study aimed to investigate the efficacy of COST (MW ≈ 1000 Da) against high-fat diet (HFD)-induced obesity and metabolic syndrome in Bama pigs.Bama pigs were fed a HFD for 12 weeks to establish an obesity model, followed by 12 weeks of oral COST administration. Serum biochemical parameters, tissue indicators, histopathology, and gene/protein expression related to cholesterol metabolism were analyzed. Fecal bile acid (BA) profiles, gut microbiota composition, and short-chain fatty acid (SCFA) levels were also examined.COST treatment significantly attenuated weight gain and improved multiple components of metabolic syndrome, including insulin resistance, dyslipidemia, and inflammation. Mechanistically, COST upregulated intestinal ABCG5/ABCG8 to promote cholesterol excretion, increased ABCA1 expression in intestine and liver to enhance reverse cholesterol transport (RCT), and upregulated hepatic LDL-R to facilitate LDL-C clearance from circulation while modulating hepatic cholesterol synthesis via SREBP2 downregulation and RNF145 upregulation. These transcriptional changes were confirmed at the protein level for LXR, LDL-R, and ABCA1. Additionally, COST decreased fecal secondary BA levels, reshaped gut microbiota composition, and increased SCFA production, with significant correlations among these factors.COST ameliorates protective effects against HFD-induced obesity and metabolic syndrome, potentially through the regulation of cholesterol metabolism and the modulation of the gut microbiota-BA-SCFA network.