114 Role of fiber in promoting health in nursery pigs

Abstract In swine production, use of feed antibiotics as antimicrobial growth promotant will be reduced; thus, feed alternatives to manage gut health are required to prevent post-weaning diarrhea. Dietary fiber, resistant starch, oligosaccharides, and exo-polysaccharides are carbohydrates are nutritional tools that may be part of managing gut health in pigs. Antibiotics are hypothesized to influence gut health via modulation of intestinal microbial profiles; fermentation and intestinal inflammation are considered important mechanisms. As alternative, dietary fiber sources differ in 2 key properties: fermentability and viscosity. Rapid fiber fermentation is associated with changes in microbial profiles and increased metabolite production. Recently, microbial composition was hypothesized to be less important, and it was thought that the focus should be on combined output of metabolites. Increased viscosity has been associated with increased gut content of virulence factors linked with diarrhea. Fiber properties may manipulate retention time and physico-chemical properties of the undigested residue. Starch is mostly digested and absorbed as glucose; however, resistant starch is not digested but fermented instead. Resistant starch acts as fermentable fiber but is unique, because it specifically increases digesta abundance of bifidobacteria that are associated with improved gut health. Oligosaccharides may be rapidly fermented and thereby influence intestinal microbial profiles and metabolite production. Raw materials and some feed additives both influence kinetics of fermentation and have prebiotic activity. Their kinetics of fermentation should be quantified so that it can be considered in feed formulation. Finally, exopolysaccharides from Lactobacillus reuteri and unique oligosaccharides may serve as scavenger molecules for pathogenic bacteria, e.g., enterotoxigenic Escherichia coli (ETEC), to bind to instead of adhering to the gut wall, thereby avoiding diarrhea initiation. In conclusion, dietary fiber and other carbohydrates may be important solutions to maintain gut health when antibiotics are removed as growth promotants from swine feeds.