Effects of dietary protein levels on lipid metabolism and intestinal health of hybrid grouper (♀ Epinephelus fuscoguttatus × ♂ Epinephelus lanceolatus) fed high-lipid diets

作者：Wenshan Cai, Weibin Huang, Gang Fu, Hengyang Song, Hao Liu, Menglong Zhou, Biao Li, Baiquan Lü, Yansheng Liu, Beiping Tan, Xiaohui Dong · 发表于：Aquaculture Reports · 年份：2025 · DOI：10.1016/j.aqrep.2025.103233 · 被引用次数：4 · 研究领域：Aquaculture Nutrition and Growth、Aquaculture disease management and microbiota、Animal Nutrition and Physiology

The study aims to investigate the effects of dietary protein levels in high-lipid diets (16 %) on lipid metabolism and intestinal health of hybrid grouper ( ♀ Epinephelus fuscoguttatus × ♂ Epinephelus lanceolatus ). Six experimental diets with equal lipid content (CL 16 %), but protein levels of 51 % (D1, control group), 48 % (D2), 45 % (D3), 42 % (D4), 39 % (D5), and 36 % (D6) were designed. The results showed that reducing dietary protein levels significantly influenced physiological responses. Body indices were modulated, with the viscerosomatic index (VSI) increasing at the lowest protein level and condition factor (CF) peaking at a moderate reduction. Serum lipid profile improved, marked by decreased low-density lipoprotein (LDL) and increased high-density lipoprotein (HDL), alongside enhanced lipoprotein lipase (LPL) activity and reduced liver triglycerides (TG). Liver gene expression shifted toward lipid catabolism, with downregulation of acetyl-CoA carboxylase ( acc ) and fatty acid synthase ( fas ) and upregulation of hormone-sensitive lipase ( hsl ), peroxisome proliferator-activated receptor α ( pparα ), and lipoprotein lipase ( lpl ). Intestinal health improved, reflected in increased digestive enzyme (lipase, trypsin, amylase) activities, improved morphology, and a favorable microbial shift characterized by reduced Proteobacteria and increased Firmicutes. The above results suggest that appropriate protein levels in high-lipid diets improve grouper lipid metabolis...