Effects of feeding a fish meal-free soy protein concentrate-based diet on the growth performance and nutrient utilization of red sea bream (Pagrus major )

Abstract

Two groups of red sea bream (average body weight 85 g) were fed to satiation fish meal (FM) or FM-free soy protein concentrate (SPC)-based diet (FM-sat and SPC groups respectively). A third group (FM-pair) was fed the same amount of FM as of SPC fed to SPC-sat group for 6 weeks. Growth rate of SPC group was significantly slower than of FM-sat and FM-pair groups (p < 0.05). Feed conversion ratios of FM-sat and FM-pair groups were similar and were better than that of SPC group (p < 0.05). Visceral fat somatic index of SPC group was significantly lower than of the other groups (p < 0.05), while that of the latter two groups were similar. Plasma triglyceride of FM-sat and FM-pair groups was similar and lower than the level of SPC group (p < 0.05). Trypsin activity in hepatopancreas of SPC group was significantly lower than that of other groups (p < 0.05). We suggest a low growth of SPC group was not simply related to low-feed intake. Feeding of a FM-free SPC-based diet may reduce lipid accumulation and consequently lead to low-growth performance, in red sea bream.