Effects of Dietary Mannan Oligosaccharide, Bacitracin Methylene Disalicylate, or Both on the Live Performance and Intestinal Microbiology of Turkeys

Hybrid male turkeys were fed to 18 wk of age in a completely randomized design with 10 replicate pens (18 birds each) per treatment to compare growth promoters. Four dietary treatments were used: negative control (CON), bacitracin methylene disalicyate (BMD) at 55 mg/kg to 6 wk and 27.5 mg/kg thereafter, mannan oligosaccharide (MOS) at 0.1% to 6 wk and 0.05% thereafter, and BMD and MOS at concentrations listed above. There were 3 toms/m2 (3.59 ft2/tom) on fresh pine shavings inoculated with used litter. A 6-phase feeding program was used, with crumbles the first 3 wk and pellets thereafter. At wk 6 and 18, one bird per pen was killed, and the large intestinal microbial populations, after being frozen, were enumerated (i.e., bifidobacteria, Clostridium perfringens, coliforms, enterococci, Escherichia coli, lactobacilli, and total anerobes). Body weights at wk 18 were as follows: CON, 11.87 kg; BMD, 12.46 kg; MOS: 12.56 kg; and BMD + MOS, 12.79 kg. The BMD and MOS turkeys were (P < 0.05) heavier than CON birds, and those fed the combination were significantly heavier than all other treatments. At wk 18, BMD + MOS feed conversion ratio of 2.66 was significantly lower than CON at 3.00 with BMD and MOS being intermediate (2.83 and 2.79, respectively). Mortality was not affected by treatment. The BMD and MOS each reduced large intestinal concentrations of Clostridium perfringens (log transformed data analysis) at wk 6 but not at wk 18. The BMD or MOS each improved turkey performance, and when used together, exhibited further beneficial effects.