Dietary sodium acetate and sodium butyrate attenuate intestinal damage and improve lipid metabolism in juvenile largemouth bass(Micropterus salmoides)fed a high carbohydrate diet by reducing endoplasmic reticulum stress

High-carbohydrate(HC)diets decrease the intestinal levels of sodium acetate(SA)and sodium butyrate(SB)and impair the gut health of largemouth bass;however,SA and SB have been shown to enhance immunity and improve intestinal health in farmed animals.Thus,the present study was to investigate the effects of dietary SA and SB on HC diet-induced intestinal injury and the potential mechanisms in juvenile largemouth bass.The experiment set five isonitrogenous and isolipidic diets,including a lowcarbohydrate diet(9%starch)(LC),a high carbohydrate diet(18%starch)(HC),and the HC diet supplemented with 2 g/kg SA(HCSA),2 g/kg SB(HCSB)or a combination of 1 g/kg SA and 1 g/kg SB(HCSASB).The feeding experiment was conducted for 8 weeks.A total of 525 juvenile largemouth bass with an initial body weight of 7.00±0.20 g were used.The results showed that dietary SA and SB improved the weight gain rate and specific growth rate(P<0.05)and ameliorated serum parameters(alkaline phosphatase,acid phosphatase,glutamate transaminase,and glutamic oxaloacetic transaminase)(P<0.05).And,importantly,dietary SA and SB repaired the intestinal barrier by increasing the expression levels of zonula occludens-1,occludin,and claudin-7(P<0.05),reduced HC-induced intestinal damage,and alleviated intestinal inflammation and cell apoptosis by attenuating HC-induced intestinal endoplasmic reticulum stress(P<0.05).Further results revealed that dietary SA and SB reduced HC-induced intestinal fat deposition by inhibiting adipogenesis and promoting lipolysis(P<0.05).In summary,this study demonstrated that dietary SA and SB attenuated HC-induced intestinal damage and reduced excessive intestinal fat deposition in largemouth bass.