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 1, yeast was added at 1.5, 3.0 and 6.0 g kg(-1) while penicillin, tylosin or neoterramycin were a dded at 150 mg kg(-1) into different batches of a high-fibre diet containin g 250 g kg(-1) palm kernel meal. Saccharomyces cerevisiae and antibiotics i ncreased BW, BWG, FCR, Feed intake, carcass and breast weights above the co ntrol. Small intestine weight was reduced by antibiotics, while yeast cause d a lower deposition of abdominal fat. Liver weights of different treated b roilers were similar. The performance indices were superior on penicillin a nd 3.0 g kg(-1) yeast compared to other supplements evaluated. In the secon d 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 k g(-1) crude protein diet. Performance of the chicks with additives was comp ared with unsupplemented negative and positive controls containing 180 and 210 g kg(-1) crude protein respectively. Broilers Fed with supplements had superior BW, BWG, FCR and feed intake compared to the negative control, but carcass data were similar. Dietary penicillin increased BW, BWG, feed inta ke more than other supplements, but yeast stimulated higher FCR. Data from both studies indicated that Saccharomyces cerevisiae comparatively increase d growth and carcass weight and reduce abdominal fat, therefore, it can ser ve as a natural substitute for antibiotics in broiler diet.