Dietary guar gum supplementation reduces the adverse effects of high-fat diets on the growth performance, antioxidant capacity, inflammation, and apoptosis of juvenile largemouth bass (Micropterus salmoides)

Abstract

The study aimed to explore the effects of dietary guar gum supplementation on fish growth, histology, antioxidant capacity, and expression of inflammatory and apoptotic genes in juvenile largemouth bass (Micropterus salmoides) fed high-fat diets. Five isonitrogenous diets were prepared: a control diet (10% lipid, Control), a high-fat diet (18% lipid, HF), and three high-fat diets supplemented with 0.3%, 1%, and 3% guar gum (GG0.3, GG1, and GG3 respectively). Largemouth bass (3.11 ± 0.01 g) were randomly assigned and fed for eight weeks. The results showed that dietary supplementation with 0.3% guar gum significantly increased final body weight, specific growth rate, and feed efficiency in comparison with HF (P < 0.05). For histology, high-fat diets containing guar gum significantly decreased vacuolated areas per hepatocyte and increased hepatic health status scores compared with HF (P < 0.05). Fish fed diets GG0.3 and GG1 exhibited lower malondialdehyde (MDA) contents (in the liver), higher reduced glutathione (GSH) contents (in plasma), and higher catalase (CAT) activity (in the liver) than those fed HF (P < 0.05). Furthermore, diets GG0.3 and GG1 significantly downregulated the expression of tumor necrosis factor α (TNF-α), cysteine-aspartic proteases 3 (Caspase 3), and Caspase 9 in the liver compared to HF (P < 0.05). These results suggest that guar gum can alleviate the adverse effects of high-fat diets on growth, antioxidant capacity, and hepatic health in fish.