This trial wascarried out to evaluate the effects of feeding Tilapia fillet by-products meal(TF) for piauçu (Leporinus macrocephalus) fingerlings. One hundredand twenty-five fingerlings averaging weight of 0.19 ± 0.004 g and lengthof 2.37 ± 0.28 cm were assigned to a completely randomized design withfive treatments of five replicates. The diets were formulated to contain levelsof 0, 5, 10, and 15% of TF and 0% of TF plus methionine. Diets were fed at 10%of biomass four times a day (8 a.m., 11 a.m., 2 p.m. and 5 p.m.). The meansof water abiotic parameters were 7.89 ± 0.05, 89.93 ± 0.42, 7.15± 0.10 and 27.10 ± 0.95 for pH and electric conductivity (µS.cm-1)and dissolved oxygen (mg.L-1) and temperature (ºC), respectively.At the end of the experiment, the means of survival (SO), final weight (FW),final length (FL), weight gain (WG), condiction factor (CF), and apparent feedingconversion (FC) were measured and calculated. Significant effects of treatmentson CF, CA, and FC were detected. The better results were observed with the increasinglevels of FT and supplementation of methionine. FL increased and FC decreasedlinearly with the increasing levels of TC, where the LRP model better adjustedto data when 8.56 and 8.19% of TF levels were estimated. The crude protein (PB)in the carcass presented better results for the treatments with more than 5%of FT and 0% of FT with methionine supplementation. It is recommended to includeup to 15% of FT in the diets for piauçu fingerlings to obtain betterresults of performance and CP deposition in the carcass, that becomes the FTan alternative protein source.
