Crude protein levels of ration with amino acid supplementation to gilts maintained in a thermal comfort environment from 30 to 60 kg

An experiment was conduced to determine the crude protein (CP) level in diets with amino acids supplementation for gilts maintained in a thermal comfort environment. Fifty crossbreed crossbred gilts (Landrace x Large White) with initial average weight of 30.1 kg were allotted to a completely randomized experimental design, with five treatments (19, 18, 17, 16 and 15% of CP with supplementation of lysine, methionine, tryptophan, threonine and valine to maintain the same protein quality) five replicates and two animals per experimental unit. The experimental rations were fed ad libitum until the end of the experiment, when the animals reached the average weight of 60.3 kg. The CP level of the ration influenced the daily weight gain and the feed:gain ratio however the treatments did not influence the daily feed intake. The protein deposition (PD) did not change from 19 to 16% of CP of the diet. However the animals that fed diet with smaller level showed the lowest value of PD. The treatments did not influence the absolute and relative weights of all evaluated organs. It was concluded that the crude protein level, for gilts from 30 to 60 kg, maintained in thermal comfort environment can be reduced from 19 to 15% with no negative effect on performance since rations are supplemented with limiting essential amino acids

carcass composition; ideal protein; organs; performance; thermal environment

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