The aim of this work was to verify the effect of different levels of true digestible lysine (TDL) and crude protein (CP) on diets on the carcass composition of the swine in the nursery phase. Eighty piglets Landrace x Large White, barrows and females, with initial weight of 9.1±1.2 kg and final weight of 21.5±4.8 kg, weaned at the 28 days, allotted in groups of two during 35 days in the nursery. A randomized block design in factorial 2x4 (two levels of CP - 16 and 18% - and four of TDL - 0.7; 0.9; 1.1 and 1.3%) with five repetitions was used. After weighing, one animal of each stall was sacrificed and the carcass utilized for determination of water (CWP), protein (CPP) and lipid (CLP) percentage and deposition tax of the protein (DTP) and lipid (DTL). There were no differences for CWP, but there was had quadratic effect of the lysine levels on the CPP and DTP in the carcasses only in 18% CP diets, being 1.02% of TDL that propitiated the best result for DTP. There was no difference in 16% CP diets. For the CLP, there were no differences when 18% CP diets were utilized, however there was had quadratic effect with 16% CP diets, being 0.99% the level of TDL that provided the higher deposition. For the DTL, the 1.08 and 1.00% of TDL resulting in higher values in 18 and 16% CP diets, respectively. One concluded that 18% CP diets is the ideal and the 1.02% of TDL must be kept for the best carcass composition of swine in the initial phase.
Synthetic amino acids; carcass composition; nutrition; piglets
