Influence of Dietary Inclusion of Full-Fat Soybean Meal and Amino Acids Supplementation on Growth and Digestive Enzymes Activity of Nile Tilapia, Oreochromis niloticus

The influence of replacing diet fish meal LT94 (FM) with different levels of full fat soybean meal (FFSB) on growth performance and enzymes activity in stomach, hepato-pancreas and intestine were investigated for Nile tilapia Oreochromis niloticus. Four diets (D1, D2, D3 and D4) were formulated 0, 15, 20, and 20 g/100 protein of diets + DL-methionine by replacing FFSB with fish meal respectively. Proximate composition of the diets was determined. The growth of O. niloticus was significantly decreased (P<0.05) with substitution of fish meal by FFSB (D2, D3 and D4) compared to the control group (D1). The lowest weight gain (46.02±1.30 g), specific growth rate (SGR: 2.29%±0.03), protein efficiency ratio (PER: 2.25±0.04) and apparent net protein utilization (ANPU: 36.37%±0.29) were achieved at D4. Regression analysis did not show a significant differences (P>0.05) for proteolytic and trypsin activities in the intestine and stomach among the data of all fish groups. However, hepato-pancreas proteolytic and trypsin activities showed significant decrease (P<0.05) with increase of FFSB magnitude in the diets. Activity of amylase and lipase in hepato-pancreas, stomach and intestine displayed significant differences (P<0.05) between control group and fish of the tested diets groups. The carcass composition of fish did not exhibit a significant difference.