Xylanase and Direct-Fed Microbials (DFM) Potential for Improvement of Live Performance, Energy Digestibility, and Reduction of Environmental Microbial Load of Broilers

摘要

The challenge of identifying alternatives to subtherapeutic levels of antibiotic growth promoters (AGP) in animal feed has led to increased interest in feed additives such as exogenous enzymes and direct-fed microbials (DFM). Six corn-soy-based dietary treatments were designed to investigate the effect of high-efficiency xylanase alone, Bacillus spp. probiotics alone, and their combination versus a commonly used antibiotic growth promoter (BMD; Bacitracin methylene disalicylate) on live performance, and environmental Clostridium perfringens load of broiler chickens with 8 replicate pens per treatment. Diets were: standard diet (Positive control; PC); 130 kcal/kg reduced energy diet (Negative control; NC); NC with xylanase (NC Xy); NC with probiotics (NC Pro); NC with xylanase and probiotics mix (NC XyPro); and NC with BMD (NC BMD). Data were analyzed as one-way ANOVA. At 35 and 42 d, birds fed NC XyPro and NC BMD were heavier (P0.05) than birds fed NC. Improvement in FCR (P=0.0001) was observed from 1-42 d by approximately 3 points in both NC XyPro and NC BMD compared to NC. The NC XyPro reduced lesion scores by 66% compared to PC and NC. Litter C. perfringens cell count was reduced by approximately 16% with supplementation of XyPro or BMD. It can be concluded that a blend of xylanase (10 XU/g feed) and Bacillus spp (1 x 105 CFU/g feed) can be used as an alternative to AGP in low-energy broiler diets.