This study was conducted to evaluate the difference among genetic groups and the effects of diets with different levels of metabolizable energy for broilers. The performance and carcass quality of seven genetic groups (M1C1, C1C1, C2C2, M1C2, C2F1, C1F1 and M1F1) of broilers obtained from the cross among two lines developed by UFV (M1 and F1) and two mainly trade mark lines (C1 and C2) were determined. The chickens were randomly allocated to 84 different boxes (15 birds/box and 12 replicates), where they were kept up to 42 days of age. In the initial period (1st to the 21st day of age) the birds were fed diet with 3000 kcal of ME/kg, and in the final period (22nd to the 42nd day of age) the birds were fed diets with four different levels of energy (2900, 3050, 3200 and 3350 kcal ME/kg). The analyzed characteristics were: live weight at 42nd day of age, slaughter weight and carcass and prime cut yields. Significant difference was observed among genetic groups and sex, independent of the energy level, on live weight, slaughter weight, carcass weight and prime cuts, standing out the genetic groups C1C1 and C2C2. The males presented the best results for all traits. In the study of carcass and prime cut yields, in function of the slaughter weight, there was difference among genetic groups only for breast yield.
broilers; carcass; genetic groups; levels of energy
