Two hundred and forty male broilers, Hubbard strain, with average 689±5.27 g LW maintained, from 22 to 42 days of age under heat stress (31.9±0.29ºC) conditions were used. A completely randomized design, with five treatments (3000, 3075, 3150, 3225 and 3300 kcal metabolizable energy/kg of diet), six replicates and eight animals per experimental unit was used. The effects of different levels of metabolizable energy (ME) levels on the performance, carcass quality and physiological variables of broilers fed isoproteic diets, in a controlled way (ingesting 93% of the voluntary intake) were evaluated. The weight gain and feed:gain ratio improved and the metabolizable energy intake increased linearly in reason of the metabolizable energy level of the diet. The protein and fat carcass deposition increased linearly and the absolute weight of drumstick quadraticaly in function of the dietary metabolizable energy level. The broiler fed a 3232 kcal of ME showed the best performance; however those fed 3108 kcal diets had higher protein deposition with less proportion of fat in carcass of the broilers maintained under heat stress conditions.
broiler; heat stress; metabolizable energy
