Abstract: ObjectiveThis experiment aims to investigate the relationship between dietary protein levels and growth performance, muscle quality, and biochemical parameters in Amur ide (Leuciscus waleckii), and further determine the optimal dietary protein level for its growth conditions. MethodsIn the experiment, 600 healthy L. waleckii with an average initial weight of (49.42±5.39) g were selected and randomly divided into 5 groups, with 3 replicates in each group and 40 fish in each replicate. The crude protein content of each group was 25.68%., 29.84%, 34.52%, 39.04%, 43.12% of five groups of feed with the same fat content. The experiment period is 56 days, based on the growth performance indicators including survival rate, weight gain rate, specific growth rate, feed conversion ratio, and condition factor of the experimental fish, as well as the proximate composition of muscle and relevant enzyme activities in the liver and intestine. ResultsThe results showed that the weight gain rate and specific growth rate of the test fish in the 34.52% group were significantly higher than those in the 25.68% group and 29.84% group (P<0.05). The feed coefficient of the 43.12% group was significantly lower than that of the 25.68% group and the 29.84% group (P<0.05). The crude protein content of the 34.52% group was significantly higher than that of the 25.68% group, 29.84% group and 43.12% group (P<0.05). The fat content of the 43.12% group was significantly higher than that of the 29.84% group and 34.52% group (P<0.05). The amylase activity in the intestinal tract of test fish in the 34.52% group was significantly higher than that in the 25.68% group, 29.84% group and 43.12% group (P<0.05). The lipase activity in the intestinal tract of the test fish in the 34.52% group was significantly higher than that in the other groups (P<0.05). The protease activity in the intestinal tract of test fish in the 43.12% group was significantly higher than that in the 25.68% group, 29.84% group and 34.52% group (P<0.05). The acid phosphatase of the test fish in the 34.52% group was significantly higher than that in the 25.68% group (P<0.05). ConclusionThe results showed that through polynomial regression analysis of the relationship between the weight gain rate and the crude protein level in the feed, it was concluded that the most suitable crude protein level for the sub-adult growth stage of L. waleckii was 37.52%.