| Abstrakt: |
Shuttle programs involving dietary supplementation of mannanoligosaccharides (MOS) and virginiamycin (VM) were evaluated in turkeys by their effects on growth performance, body weight uniformity, and carcass yield characteristics. Diets containing no growth promoter (control), VM (22 mg/kg), or a shuttle program (MOS-VM) of MOS (0 to 6 wk of age at 500 mg/ kg) and VM (6 to 14 wk of age at 22 mg/kg) were fed to Hybrid female turkeys. All diets were formulated to exceed NRC nutrient requirements. Each treatment was assigned to 8 replicate floor pens containing 20 birds that were reared from 1 to 98 d of age. Body weights and feed consumption were recorded at 3-wk intervals, and mortality and culled birds were recorded daily. At the conclusion of the trial, 2 birds per pen were randomly chosen for carcass yield analysis. Feeding VM alone significantly (P < 0.05) increased body weight compared with control fed birds during all periods. The MOS-VM shuttle program resulted in early growth depression for birds less than 3 wk of age, possibly influenced by an unplanned cold stress, but better growth than the nonmedicated control birds after 6 wk of age. Birds fed VM had superior (P < 0.05) feed conversion ratio from 0 to 3 wk, which persisted until 14 wk (P < 0.10). There were no treatment effects on overall feed consumption, uniformity, mortality, or cull rate. Processing yields or weight of various parts were also unaffected by treatment. |
