Digestible lysine requirement for Tambaqui (Colossoma macropomum) juveniles using the diet dilution technique

Lysine requirements of tambatinga (♀ Colossoma macropomum × ♂ Piaractus brachypomus ) fingerlings using different diet formulation techniques

“…The results were similar to those obtained by Silva et al (2018) and Marchão et al (2020), who did not observe any feed intake variation with the increasing digestible lysine levels in diets of tambaqui juveniles (Colossoma macropomum), using diets formulated by supplementation technique and dilution technique, respectively. Whilst different results were obtained by Bomfim et al (2010) in Nile tilapia and Encarnação et al (2004) in rainbow trout (Oncorhynchus mykiss Walbaum).…”

“…Thus, we can infer that the significant differences found in other parameters are due to the increase in lysine level that optimized each response. In the case of the dilution technique, lysine was maintained as the first limiting essential amino acid in the protein fraction at all treatments, similarly to the procedure performed by Marchão et al (2020), even in diets containing increasing levels of crude protein (214.6 to 375.6 g kg −1 ). The higher weight gain of fishes fed with diets formulated by the dilution technique can be due to the lower concentration of crystalline amino acids.…”

“…The upper weight category of tambaquis in experiment conducted for Marchão et al (2020) implied the lower growth rate…”

“…The increase in the weight gain, associated with similar feed intake, resulted in the improvement of feed conversion ratio until the 19.28 g kg −1 total lysine level. This improved indicate that there was increase in body protein deposition, since the lean tissue deposition (protein) is more energy efficient than the fat deposition, because it adds more amount of water in its composition (Bomfim et al, 2010;Marchão et al, 2020;Sousa et al, 2018).…”

“…This diet is diluted in a protein-free isoenergetic diet, thereby resulting in intermediate levels of the test amino acid. The main advantage, in this case, would be the use of lower crystalline amino acid levels, which would favour the determination of amino acid requirements in experiments with non-ruminant animals (Liebert & Benkendorff, 2007;Marchão et al, 2020;Rostagno et al, 2007;Siqueira et al, ,2009Siqueira et al, , , 2013. In studies with fish for determination of amino acid requirements, there is an intensification in the use of this technique (Bomfim et al, 2020;Liebert, 2009;Marchão et al, 2020).…”