LAUSR

Abstract Among plant protein sources, soy protein concentrate (SPC) has lower anti-nutritional factors and higher protein content. The aim of this study was to evaluate the effect of replacing fish meal in diet of rice field eel Monopterus albus with soy protein concentrate on growth performance, serum biochemical indices, intestinal digestive enzymes and growth-related genes expression in skeletal muscle. Six isonitrogen (45% crude protein) and isolipidic (5.5% crude lipid) diets were formulated with 0 g/kg, 8.5 g/kg, 17 g/kg, 25.5 g/kg, 34 g/kg and 42.5 g/kg SPC inclusion to replace 0%, 15%, 30%, 45%, 60% and 75% of fish meal (S0 (control), S8.5, S17, S25.5, S34, S42.5, respectively). Each diet was randomly assigned to triplicate groups of 100 fish per net cage (mean initial weight 25.56 ± 0.12 g). The fish were fed once at 18:00 per day for 56 days. Results showed that weight gain and feed intake significantly decreased in fish fed S42.5 (P