ECONOMIC ANALYSIS OF FEEDING TILAPIA IN CAGES WITH DIGESTIBLE PROTEIN AND ENERGY LEVELS

We evaluated the economic responses of Nile tilapia in the final stage (450 to 800 g) fed diets containing five levels of digestible protein (DP): 20, 23, 26, 29 and 32% and two digestible energy levels (DE): 3,000 and 3,300 kcal kg(-1) based on the sale of whole animals or fillet. This experiment was carried out into 50 m(3) net cages in an aquaculture area located in Paranapanema River, Palmital - Sao Paulo State, Brazil, from November 21st, 2010 to January 21st. Economic performance indicators were: gross revenue, partial production cost, net revenue, leveling point, balance point, benefit cost ratio and cost of feed kg(-1) gain. Twenty-nine percent of DP and 3,000 kcal DE kg(-1) diet provided better economic performance for sale of whole fish, meaning higher net revenue (R$ 23.09 net cage(-1)) and benefit cost ratio (1.08), besides the lowest balance point (R$ 3.91 kg-1). Thirty-two percent of DP and 3,000 kcal DE kg-1 diet provided the lowest cost of feed kg(-1) (R$ 2.53), leveling point (17.35 kg net cage(-1)) and balance point (R$ 13.63 kg(-1)), besides the highest benefit cost ratio (1.54) when the fish were sold in fillet form. Diets with 29% and diet with 32% digestible protein, both of them with 3,000 kcal of digestible energy kg(-1) diet provides better economic responses in Nile tilapia reared in net cages (450 to 800 g), to be sold, respectively, whole or fillets form.