The Influence of Galactooligosaccharides on Nutrient Digestion, Ileal and Fecal Fermentation Characteristics, and Intestinal and Colonic Microflora in Growing Swine

153 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2002.Experiments were conducted to evaluate fermentative and prebiotic effects of galactooligosaccharides (Gal OS) in pigs. The first experiment measured in vitro fermentation of Gal OS in comparison to other oligosaccharide (OS) sources using swine fecal microflora. The second experiment evaluated increasing concentrations of soybean OS on apparent and trae ileal amino acid digestibilities. The third experiment evaluated Gal OS supplementation of pig diets to determine effects on nutrient digestibility, microbial populations, and ileal short-chain fatty acid (SCFA) concentrations. Additionally, the third experiment measured in vitro fermentation of Gal OS using swine ileal effluent prior to and after six weeks of dietary adaptation to Gal OS. Overall, these experiments demonstrated that Gal OS are rapidly fermentable in vitro by both swine ileal and fecal microflora and function as prebiotics in vivo by increasing concentrations of beneficial bacteria. Pure Gal OS fermentation with swine fecal and ileal microflora occurred more rapidly in vitro and resulted in a higher rate of fermentation and greater amounts of gas and SCFA produced when compared to the soy by-product, soy solubles (SS), when similar concentrations of active ingredients were assessed. The fermentatioe characteristics of SS were similar to FOS and GOS. In vivo, when Gal OS were supplemented at up to 3.5% of the diet as SS that were part of a practical diet, apparent and true ileal amino acid digestibilities were minimally affected. However, when 3.5% Gal OS was supplemented to more refined diets as either SS or TOS, there was up to a 5.5 percentage unit depression in apparent ¡leal and total tract nutrient digestibilities. Inclusion of 3.5% Gal OS as SS or TOS increased fecal beneficial bacterial concentrations. Supplementation of swine diets with Gal OS positively influenced microbial populations and gastrointestinal fermentation. Whether the improvement in gut microbial populations outweighs the depression in nutrient digestion remains to be determined, but is doubtful given the relatively brief lifetime of the market pig. However, this might be impacted by a future swine production system that decreases or eliminates use of sub-therapeutic concentrations of antibiotics in practical diets fed to swine.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD