Dietary protein reduction for Nile tilapia fingerlings reared in biofloc technology

The objective of this study was to evaluate the growth performance of Nile tilapia fed diets with 28, 32, and 36% crude protein (CP) in biofloc technology (BFT) and to verify its influence on water quality and hematological parameters. The experimental design was completely randomized with three treatments (28, 32, and 36% CP) and six replicates. Nile tilapia (n = 270, 6.31 +/- 0.40 g) were randomly distributed in 18 aquaria-200 L (15 fish/aquarium), over a period of 60 days. No differences (p > .05) were observed among the treatments for the growth performance and hematological parameters. The volumes of nitrite and sedimentable solids showed higher values with 36% CP, which differed (p < .05) in comparison to 28% CP. Different levels of dietary CP content (36, 32 and 28% CP) do not influence the growth performance and health of Nile tilapia (6-25 g) reared in BFT. Thus, an 8% reduction in dietary protein (28% CP) can generate savings in terms of the costs of production and can decrease the environmental impact of excess dietary protein.