-propiothetin (DMPT) on growth, proximate muscle composition, and protein metabolism in =1 800, average initial body weight: 4.20±0.02 g) were cultured in a flow through system. The fish were randomly divided into six triplicate groups of 100 fish and fed diets containing different levels of DMPT (0, 0.25%, 0.5%, 0.75%, and 1.0%) for 56 d. Weight gain rate was highest at 0.2% DMPT supplementation (<0.05). The optimum supplementation was 0.24% based on a polynomial regression analysis between dietary DMPT level and weight gain rate. Serum total protein, albumin, and globulin increased significantly with 0.05% DMPT supplementation (<0.05) and serum total protein, globulin and serum aspartate aminotransferase increased significantly with 0.2% DMPT supplementation (<0.05). Meanwhile, liver and muscle protein levels and protease activity in the digestive track increased significantly as dietary DMPT supplementation increased between 0.02% and 0.5% (<0.05). The liver somatic index increased significantly with 0.05% DMPT supplementation. DMPT supplementation had no effect on muscle crude lipid, ash, amino acid profile, or serum alanine transaminase (0.05). Our results suggest that growth performance and protein levels were improved by dietary DMPT supplementation in taimen and 0.02%–0.5% DMPT supplementation can increase the protein storage in muscle and liver.