The objective was to evaluate levels of digestible lysine in diets with 5ppm of ractopamine on performance and carcass characteristics of finishing pigs. Ninety-six pigs, 48 barrows and gilts with initial body weight of 83.57 ± 4.07kg, were sorted in a complete randomized design with four levels of digestible lysine (0.94; 0.96; 1.02 e 1.04%), with three replications and eight animals each. The experimental period lasted 28 days. The feed intake was reduced and feed:gain ration improved linearly with increase digestible lysine levels in diets. Final, slaughter and hot carcass weights, carcass yield, amount of lean meat and payment index increase linearly with increase of digestible lysine levels. There was no effect of digestible lysine levels on daily gain, farm to slaughter shrink and lean meat percent. In conclusion, in diets with 5 ppm ractopamine, 1.04% digestible lysine improve feed:gain ration and increase final weight, carcass weight and yield, amount of lean meat and payment index of carcass of pigs.
additives; beta-adrenergic; carcass; lean meat