Addition of solid-state fermentation product of yeast ameliorated the effects of high-fat diet on hepatic lipid metabolism, epidermal mucus, intestine and liver health, and gut microbiota of zebrafish

To assessed the effects of solid-state fermentation product of yeast (SFPY) supplementation on high-fat diet (HFD) induced challenges on growth, hepatic lipid metabolism, epidermal mucus, intestine and liver health and gut microbiota in zebrafish (Danio rerio), four experimental diets were prepared for one-month-old zebrafish: basal diet (Control), high-fat diet (HFD), 0.5% SFPY (0.5 SFPY) or 1.0% SFPY (1.0 SFPY)-added HFD. After 3 weeks of feeding, the results illustrated that although HFD increased weight gain (WG), corresponding decreased the feed conversation ratio (FCR), it caused negative influences including liver steatosis, intestinal and liver damage in zebrafish. Compared with HFD group, 1.0% SFPY obviously promoted the lysozyme activity and complement 4 (C4) level on epidermal mucus (P < 0.05), and significantly reduced liver TAG (P < 0.05). Addition of SFPY significantly decrease the lipid synthesis-related genes including C/EBP alpha, FAS, PPAR gamma, ACC1, DGAT2 and pro-inflammatory factors including IL-6, IL-1 beta in liver (P < 0.05), significantly increased the height of gut villi (P < 0.05). Moreover, the 1.0 SFPY group significantly reduced the abundance of gut microbiota concluding Proteobacteria, Fusobacteriota, Planctomycetota and improved the abundance of gut Actino-bacteriota and Firmicutes (P < 0.05). To sum up, the addition of SFPY significantly ameliorated hepatic inflammation and intestinal damage caused by high-fat diet, and positively affected the intestinal microbiota composition of zebrafish.