Previous studies suggested that dietary supplementation with prebiotic fructooligosaccharides (FOSs) and polyphenols could mitigate disorders related to the first stage of nonalcoholic fatty liver disease (NAFLD) induced by an obesogenic diet. Therefore, this experiment aimed to address whether the health-promoting potential of raspberry polyphenols together with FOSs can regulate advanced-stage NAFLD in Zucker rats genetically predisposed to develop obesity. The addition of FOSs and raspberry polyphenolic extract to the diet reduced liver fat accumulation and triglyceride, free fatty acid, and total cholesterol levels in the liver. The elevated GSH/GSSG ratio and reduced malondialdehyde content indicated that the liver antioxidant potential was considerably increased. The treatment also lowered the plasma aminotransferase and alkaline phosphatase activities and collagen type IV levels. Insulin levels were decreased, but glucose levels remained constant, indicating greater insulin sensitivity. These changes may result from the upregulation of FXR and AHR receptors in the liver, which are responsible for regulating lipid metabolism and glucose and bile acid synthesis. The reduced bile acid levels in the cecal contents confirmed the activation of liver mechanisms. In conclusion, dietary enrichment with FOSs and raspberry polyphenolic extract has sufficient health-promoting potential to regulate liver metabolism, oxidative stress, and inflammation related to NAFLD development in obese Zucker rats.
Keywords: AHR receptor; FXR receptor; Zucker rat; anthocyanins; ellagitannins; lipid metabolism; liver disorder; obesity; prebiotics; raspberry polyphenolic extract.