Effects of dietary fish meal replacement with protein mixtures on growth performance, biochemical composition, and physiological metabolism of juvenile swimming crab, Portunus trituberculatus

Abstract

A feeding trial was conducted to investigate the effects of different levels (0%, 16.67%, 33.33%, 50%, and 66.67%) of fish meal replacement by protein mixtures on the growth, body composition, and physiological metabolism of juvenile swimming crabs, Portunus trituberculatus. The results showed that the final body weight (FBW), weight gain rate (WGR), specific growth rate (SGR), intermolt duration (ID), and hepatosomatic index (HSI) initially increased and then decreased with increasing dietary fish meal replacement levels, and the highest FBW, WGR, and SGR values were found in crabs fed Diet 3. The crude protein content in the body significantly decreased, whereas the moisture and ash contents increased significantly with increasing fish meal replacement levels. The digestive enzyme activity of crabs was significantly affected by different levels of fish meal replacement with protein mixtures. The highest glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) levels in the hepatopancreas were detected in crabs fed Diet 5. The serum superoxide dismutase (SOD) activity increased significantly with increasing fish meal replacement levels. In conclusion, the results of this study indicated that the appropriate dietary fish meal replacement level is approximately 33% with no significant negative effects on the growth performance of juvenile P. trituberculatus.