The trial was carried out to evaluate different blends of plants extracts in broilers diets. It was used 1,350 broilers distributed in a randomized block design with six replicates and five diets, one without additive and the four others, each containing one of the following additives: 10 ppm of avilamycin; 200 ppm of a product containing essential oils of carnation, thyme, cinnamon and microencapsulated capsicum; 100 ppm of a product containing essential oils of synthetic cinnamaldehyde and carvacrol and capsicum oleoresin microencapsulated; 500 ppm of a commercial product containing eucalypt oil, essential oil of Chinese cinnamon, leaves of Chilene boldo and seeds of fenu-Greek at the initial phase and 1200 ppm in the grower and finisher phases. Performance parameters were evaluated at 21 and 42 days of age and the carcass characteristics at 44 days of age. From 27 to 30 days of age, it was carried out the metabolism trial trough total excreta collection method and metabolizable energy and the crude protein digestibility of the diets were determined. The diets with plant extract blends had no significant effect on the performance when compared to diet without additives or diet with avilamycin. The lack of challenge in the experimental facilities and the use of diets with high digestibility ingredients might have contributed to broilers express all their potential making undetectable the improvement made by the inclusion of any of these additivies. Diets with plant extract blends promote performance similar to those obtained with diets containing avilamycin.
additives; carcass characteristics; metabolic assay; performance
