Evaluation of the use of probiotics in diets with or without growth promoters for broiler chicks

This work was carried out to evaluate the use of Bacillus subtilis probiotic C-3102 (10(10)cfu/g) in diets with or without growth promoters on the performance of broilers in the period from 1 to 42 days of age. It was used 1,200 Cobb line broilers, distributed in a complete randomized block with five diets: negative controller (without promoters); Bacillus subtilis (30 g/t ration); Bacillus subtilis (50 g/t ration); Bacillus subtilis (30 g/t ration) + colistin (10 ppm); avilamycin (10 ppm) + colistin (10 ppm). Each diet was evaluated in 10 repetitions with 24 birds. From 21 to 42 days of age, feed intake, weight gain and feed conversion were evaluated, and at 42 days of age, productive efficiency index was evaluated. At the end of the experimental period, it was observed an increase in the consumption of diet with the lowest dose of Bacillus subtilis (30 g) in relation to that one with Bacillus subtillis (30 g) + colistin (10 ppm). The values of weight gain obtained with the diet with the lowest dose of Bacillus subtillis (30 g) and with avilamycin (10 ppm) + colistine (10 ppm) were higher than those of the birds fed control diet (without promoters). For feed conversion, the best results were obtained by supplying diets containing 50 g of Bacillus subtillis, diet with 30 g of Bacillus subtillis + 10 ppm of colistin; and diet with 10 ppm of avilamycin + 10 ppm colistin. For the analysis of productive efficiency index, the best results were obtained with diets containing additives (probiotics and/or antibiotics) in comparison to the control diet. Bacillus subtillis C-3102 probiotic, at concentration 10(10) cfu/g, is an efficient substitute of antibiotics