The effects of mannanoligosaccharides and sub-therapeutic antibiotics on the growth performance, gastrointestinal characteristics, and immune function of large white turkeys

The purpose of this research was to further understand the mechanisms by which dietary mannanoligosaccharides (MOS) and antibiotics influence the growth performance of Large White turkeys. The goals of the research were two-fold: (1) to ascertain the effects of dietary MOS and antibiotics on growth performance, and (2) to investigate the influence of the intestinal microflora on host physiology and immunological status.; The series of studies concluded that MOS, Bambermycins (BM), and Virginiamycin (VM) improved early feed conversion, whereas VM improved feed conversion for wk 0–12 and 0–18. All treatments significantly (P < 0.05) increased 20 wk BW compared to control birds. Observations on the physical aspects of the intestines in 12 wk old male turkeys after feeding dietary MOS, BM, and VM indicated that VM caused a significant decrease in the weight and length of digestive tract sections, while feeding BM and MOS had little or no effect on physical measurements. Mannanoligosaccharides, VM, and BM altered jejunal and cecal VFA production, while VM increased the pH of the jejunal contents. Neither MOS, VM, nor BM had any effects on dietary metabolizable energy. Feeding VM from 6–14 wk of age impacted latter trial performance to the same degree as feeding VM from 0–14 wk of age. However, MOS failed to influence performance when fed in a shuttle program (0–6 wk of age) followed by VM (6–14 wk of age). Carcass composition was unaffected by treatment. Virginiamycin and MOS had significant influences on the morphology and physiology of the GI tract, as indicated by alterations in crypt depth, goblet cell numbers, and lymphoid organ weights, while antibody titer was largely unaffected by treatment.; In conclusion, the results indicate that MOS and antibiotics improve the growth performance of commercial turkeys via their combined effects on the physical, microbial, and immunological aspects of the host animal.