Poultry viscera meal is an ingredient derived from a poultry by-product that has an adequate amino acid profile and could be a substitute for fishmeal in aquafeeds for carnivorous species with commercial interest, such as Arapaima gigas. Nevertheless, changes in the formulation of diets could alter the proximate composition of the fish produced in aquaculture. The present study aimed to evaluate the proximate composition of the meat of A. gigas fed with diets containing poultry viscera meal as a substitute for fishmeal.
Five isonitrogenous (450.20 g kg-1 of CP) and isocaloric (4,473.61 kcal kg-1 of GE) diets, with similar GE:CP ratio (9.94), were formulated with an increasing percentage replacement of fishmeal by poultry viscera meal (PVM) (0PVM, 25PVM, 50PVM, 75PVM, 100PVM). A completely randomized design was applied with 5 treatments (diets) and 4 repetitions each. 200 juvenile A. gigas (126.25 ± 3.98 g; 30.74 ± 1.26 cm) were distributed in twenty 500-L tanks (10 fish/tank) in an indoor open system with constant water renovation (flow rate: 1.50 L min-1) and 12 h photoperiod. The fish were fed to apparent satiation four times daily for 60 days. At the end of the trial, the meat was collected from two fish per tank, and the proximate composition was evaluated. Data were analyzed by one-way ANOVA and Tukey’s test (p<0.05).
The moisture (769.21±5.84 g kg-1) and crude protein (150.17±4.16) contents were not affected by increasing percentage replacement of fishmeal by PVM in diets (p>0.05). The lipid and ash contents showed statistically similar values in fish fed with 25PVM, 50PVM, 75PVM, and 100PVM (p > 0.05). However, fish fed with 0PMV presented lower lipid content than fish fed with 75PVM and 100PVM, as well as lower ash content than fish fed with 50PVM, 75PVM, and 100PVM (p < 0.05). Higher levels of fishmeal replacement by HPV increase the lipid and ash content in A. gigas meat. However, a 56.00% replacement of fishmeal is recommended based on zootechnical characteristics associated with this research.