Comparison of the supplemental effects of Saccharomyces cerevisiae and antibiotics in low‐protein and high‐fibre diets fed to broiler chickens

Two experiments were completed to compare the supplemental effects of yeast Saccharomyces cerevisiae and sub‐therapeutic antibiotics in high‐fibre and low‐protein diets for broiler chicks. In experiment I, yeast was added at 1.5, 3.0 and 6.0gkg‐1 while penicillin, tylosin or neoterramycin were added at 150 mg kg‐1 into different batches of a high‐fibre diet containing 250 g kg‐1 palm kernel meal. Saccharomyces cerevisiae and antibiotics increased BW, BWG, FCR, feed intake, carcass and breast weights above the control. Small intestine weight was reduced by antibiotics, while yeast caused a lower deposition of abdominal fat. Liver weights of different treated broilers were similar. The performance indices were superior on penicillin and 3.0 g kg‐1 yeast compared to other supplements evaluated. In the second experiment, 1.5 and 3.0 g kg‐1 of yeast, and 0.75 mg kg‐1 of procaine penicillin, zinc bacitracin and tylosin were separately added to a 180 g kg‐1 crude protein diet. Performance of the chicks with addi...