This study aimed to investigate the effects of dietary tryptophan (Trp) on growth performance and muscle quality of Procambarus clarkii. Six experimental diets with graded Trp concentrations (0.05%, 0.13%, 0.29%, 0.43%, 0.56%, 0.69%; designated Trp0.05 to Trp0.69) were fed to crayfish for 8 weeks. Growth parameters, muscle proximate composition, texture, histology, related gene expression, and intestinal microbiota were measur...