An experiment was carried out to evaluate the effects of metabolizable lysine (LM) and metabolizable energy (EM) on uni and multivariable of performance and carcasses of broilers, maintaining the ideal protein balance. Were used 2808 male chicks from a commercial line from 1 to 21 days and allotted to 104 pens. The treatments resulted from a factorial arrangement of three ME levels (3,000, 3,100 and 3,200 kcal/kg) and four LM levels (0.92, 1.02, 1.12 and 1.22%) plus another treatment on which amino acids were supplied on total basis. Eight replicates per treatment were installed according to the initial weight. Diets were based in corn and soybean meal plus crystalline amino acids. The studied variables were related with the performance, tissue deposition and the multivariate canonical variable (CAN). The last was created from primary variables such as weight gain, feed intake and protein deposition in carcasses. There was significant effect for LM, ME and the interactions on performance tissue deposition and CAN. By the broken line model, CAN allowed to estimate LM requirement at 1.18% when the diet has 3,000 kcal of ME/kg. In this work, among studied models, the linear was better to estimate the requirement at 1.22 % of LM when diets contained 3,100 or 3,200 kcal ME/kg, not reaching the optimum level, that could be at higher level.
amino acids; carcass; fat; ideal protein; multivariate analysis
