An experiment was conduced to evaluate crude protein (CP) levels and amino acid supplementation for gilts from 30 to 60 kg maintained in a high environmental temperature (air temperature of 30ºC; relative humidity of 66.1% and BGHI of 79.7). Fifty crossbreed gilts (Landrace X Large White) with an average initial weight of 30.2 kg were allotted to a randomized experimental design with five treatments and five replications and two animals per experimental unity. The treatment consisted of five levels o CP (19, 18, 17, 16, and 15%) in the ration and of the supplementation with lysine, methionine, tryptophan, threonine and valine to maintain the same protein quality of the ration. The experimental diets were given ad libitum until the end of the experiment when the animals reached the average weight of 60.1 kg. No effect of dietary level of crude protein was observed on pig performance (feed intake, weight gain and feed:gain ratio). Neither carcass protein deposition was influenced by reduction of dietary of dietary level of CP. Animals fed 18% CP showed the best carcass protein deposition. The protein levels did not influence the absolute and relative weights of the pig organs. Dietary CP level can be reduced by 4% (from 19 to 15% of CP) without any effect on performance of gilts from 30 to 60 kg maintained in a high environmental temperature since that the rations be adequately supplemented with all essential limiting amino acids.
gilts; heat stress; ideal protein; organs; performance
