Evaluation of the use of probiotic (Bacillus subtilis C-3102) as additive to improve performance in broiler chicken diets

The objective of this experiment was to evaluate the use of probiotic based upon Bacillus subtilis C-3102 (BS) in broiler diets containing or not conventional additive growth-promoter (AGP). A total of 1,824 one-day-old chicks of the Cobb-500 strain were used and distributed into 48 plots (1.50 × 2.00 m). A completely randomized design with four treatments and 12 repetitions was adopted. The treatments evaluated were: 1- Negative Control - AGP-free diet (NC); 2 - Positive Control, with AGP halquinol 30 mg/kg diet (PC); 3 - NC + BS (3x10(5) cfu/g diet); and 4 - PC + BS (3x10(5) cfu/g diet). The diets were on corn, soybean meal and meat and bone meal basis, formulated according to the nutrient allowances of the Strain Cobb Guide, following a feed program with three diets (starter, grower and finisher). At 21 and 42 days of age, feed intake, weight gain and feed conversion were evaluated, and carcass yield characteristics were determined at 42 days of age. Throughout the trial period (starter and total phases), better feed conversion was found for broilers fed diet with both additives (AGP and BS) combined. At the end of the experiment (1 to 42 days), the highest weight gain also occurred in broilers fed diets with a combination of the two additives. In present study, the use of BS or AGP alone in diets did not affect the performance of broilers. The carcass yield was not influenced by the use of the additives and beneficial effects of supplementation of BS and AGP combined in the diet on broiler performance were observed.