The objective of this study was to evaluate the effects of different additives on broiler performance and meat quality. A total of 1620 one-day-old male Cobb broilers were distributed by a completely randomized experimental design into 5 treatments: positive control - zinc bacitracin (PC); negative control - without additives (NC); probiotic 1 - 10.000 g/ton (PR-I); probiotic 2 - 500 g/ton (PR-II); and probiotic 3 - 50 g/ton (PR-III). The PC treatment promoted better weight gain (WG) than PR-II (1-28 days) and PR-III (1-14; 1-28 days), better feed conversion (1-40 days period), and the highest WG among all treatments (p<0.05). The performance of broilers fed probiotics was not different than those in the negative control group in any rearing phase, but there were performance differences among probiotic-treated birds. Hot and cold carcass yields and breast pH were not influenced by the different additives as compared to the negative control treatment. The only observed differences were in breast color (a*) and carcass yield between PR-III and the negative control group. Probiotics increased water holding capacity (except for PR-II) (p<0.05). The treatment with antibiotic promoted the highest WG. Meat quality suffered little influence from the different additives.