Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Animal Science (Animal, Dairy, and Poultry Sciences)

First Advisor

Lee Southern


Five experiments were conducted to evaluate the effects of mannan oligosaccharides (Bio-Mos) on growth performance, carcass characteristics, and pork quality of pigs. The first two experiments evaluated 0.20 and 0.30% Bio-Mos. The data indicated that the 0.20% level of Bio-Mos was more effective, and this level was used in the remainder of the experiments. Interactive effects of Bio-Mos and excess dietary Zn were evaluated in Exp. 2 and 3 and Trial 2 of Exp. 4. In Trial 1 of Exp. 4, Bio-Mos was fed with and without an antibiotic. In addition to the weanling pig experiments, 0.30% Bio-Mos was fed to finishing pigs to determine the effect on growth, carcass traits, and meat quality. Bio-Mos addition did not affect growth performance (P > 0.1) in any phase of production in Exp. 1. However in Exp. 2 and 3, Bio-Mos increased ADG during Phase 2. Bio-Mos is not effective if Zn is included in the diet. Bio-Mos did not affect growth or carcass response variables in finishing pigs. Three experiments were conducted to evaluate the effects of dried brewers yeast (BrewtechRTM) on growth performance of nursing and weanling pigs. Experiment 1 was conducted to determine the effect of dried brewers yeast (BrewtechRTM) fed to nursing pigs and subsequent growth performance during the nursery period. Experiment 2 evaluated the effect of BrewtechRTM on growth performance of weanling pigs during a 7 d Phase 1 period. In Exp. 3, 5% BrewtechRTM was compared with 5% spray-dried animal plasma and weaning pig growth was evaluated. In the nursery period, pigs fed diets containing BrewtechRTM had increased ADG and gain:feed in Phase 1 and increased ADG overall compared with pigs not fed BrewtechRTM. BrewtechRTM did not affect growth performance of pigs during Phase 1, unless BrewtechRTM was fed pre-weaning, but BrewtechRTM increased ADG and gain:feed in Phase 2, and increased gain:feed in the overall data. One experiment was conducted to determine the effects of Cr (0, 200, or 1,000 ppb) as Cr picolinate on sow productivity. Chromium supplementation at 200 ppb increased total number of pigs born and weaned. The 1,000 ppb level had no effect.