Lysine requirements of tambatinga (♀ <i>Colossoma macropomum</i> × ♂ <i>Piaractus brachypomus</i> ) fingerlings using different diet formulation techniques
Marilene da Costa Sousa, M. A. D. Bomfim, Felipe Barbosa Ribeiro, Jefferson Costa de Siqueira, Rafael Silva Marchão, Thalles José Rêgo de Sousa, Sylvia Sanae Takishita
Abstract
This study aimed to determine the lysine requirement in tambatinga fingerlings (Colossoma macropomum × Piaractus brachypomum) using different diet formulation techniques. A total of 1,800 fingerlings (0.82 ± 0.39 g) were fed for 52 days with six isoenergetic diets (3,000 kcal energy kg−1) containing different levels of lysine (12.9, 14.8, 16.6, 18.5, 20.4 and 22.2 g kg−1) were formulated using amino acid supplementation and diet dilution techniques. There was a linear effect on lysine intake and a quadratic effect for weight gain, specific growth rate, feed conversion ratio, lysine efficiency for weight gain and fish body protein deposition up to estimated levels of 19.15; 19.43; 19.28; 15.92 and 19.27 g kg−1, respectively. Fish-fed diets formulated by the dilution technique exhibited higher performance and body protein deposition. Body fat deposition and nitrogen retention efficiency of fish-fed diets formulated by the supplementation technique increased up to estimated levels of 17.96 and 19.06 g kg−1, respectively. The recommended lysine level in diets for tambatinga fingerlings is 19.27 g kg−1, for providing greater performance and body protein deposition of fishes, and dilution technique can be used in experimental fish diets formulation.