Digestible energy levels for swines from 30 to 60 kg maintained in a thermoneutral environment

Two experiments were conducted to evaluate the effects of digestible energy (DE) levels on performance and carcass gain composition. Fifty crossbred gitts and 50 crossbred barrows, from 30 to 60 kg, maintained in a thermoneutral environment, were used. The experimental design was a randomized blocks with five treatments (3100, 3250, 3400, 3550, and 3700 kcal de DE/kg of diet), five replicates and two animals per experimental unit. In the experiment with gilts the DE level did not influence daily weight gain, feed intake and protein intake of animals. Feed:gain ratio and DE intake improved linearly on the increasing dietary DE levels. In the experiment with barrows, the DE level did not influence the daily weight gain, while the feed and protein intake linearly decreased. The feed:gain ratio linearly improved and the DE intake did not vary on the increasing dietary DE levels. The dietary DE levels did not influence the protein deposition rate, but the fat deposition rate increased in a quadratic way in the gilts and linearly for the barrows. The best performance results for barrows were obtained with the level of 3582 kcal DE, and for gilts, the best results of feed:gain ratio was obtained for 3700 kcal of DE/kg.