Impact of dietary phytase on tilapia performance and biofloc water quality

We tested the hypothesis that fate of dietary phosphorus will not differ among a dicalcium phosphate-free practical diet treated with 6-phytase (3000 FTU/kg; Quantum Blue™; P-F + Phy), and positive (C) negative (P-F) control diets when fed to hybrid tilapia (Oreochromis aureus x O. niloticus; 29.8 g initial weight) stocked at 29 fish/m3 grown for 5 months market size (454 g/fish) in outdoor biofloc production system tanks (16.6 m3). The ideal protein were formulated contain 27.7% digestible 4% lipid from ingredients extruded commercially. Final weights (467–494 g), weight gains (1636-1723%), average daily intake (2.10–2.18%) did fish Phy or C diets; however, these metrics significantly lower treatment. There fewer (46.8–54.7%), feed conversion ratios poorer (1.59–1.61), intraperitoneal fat contents (6.96–7.40%) higher phosphorus-free compared (65.3%, 1.46, 5.90%). Geosmin, as 2-methylisoborneol, was considered more relevant off-flavor compound fillet concentrations than those but present each unlikely cause “earthy” “musty” off-flavors. Accumulation rates soluble reactive phosphorus, organic total nearly half observed while loading 37.7% lower.