This study aims to evaluate the effects of dietary glutamine on the growth performance and hepatic‐intestinal health of loach, Paramisgurnus dabryanus . Loaches were fed diets with graded glutamine concentrations of 0% (control), 0.25%, 0.50%, 0.75%, 1.00%, and 1.25% for 8 weeks. The results indicated that inclusion of 0.75% and 1.00% glutamine in the diet significantly improved the weight gain rate (WGR) and specific growth rate (SGR), and the optimal supplementation level of glutamine in the diet was 0.74% based on quadratic regression analysis of WGR. Further biochemical and histological analyses revealed that the 0.75% glutamine group demonstrated significant elevations in hepatic aspartate transaminase (AST), glutathione peroxidase (GPX) and catalase (CAT) activities, glutathione (GSH) and immunoglobulin M (IgM) contents, and intestinal amylase activity relative to the control ( p < 0.05). Moreover, the intestinal villus height (VH), villus width (VW), and muscular layer thickness (MT) were increased with the increasing concentration of glutamine in the diet, reaching their peak values in the 1.00% glutamine group. In summary, 0.74% dietary glutamine is recommended to optimize growth performance and hepatic‐intestinal health in loach.
Li et al. (Thu,) studied this question.