Dietary antibiotics will be used less as growth promotant; thus, alternatives are investigated. Some efforts are focused on using feed additives as alternatives, but macronutrients in feedstuffs may also be part of a toolkit to manage gut health in pigs. Dietary carbohydrates include starch, fiber (non-starch polysaccharides) and oligosaccharides. Antibiotics are hypothesized to control gut health via manipulations of intestinal microbial profiles or reduced intestinal inflammation. Starch is mostlydigested and absorbed as glucose; however, resistant starch is not digested but fermented. Resistant starch acts as fiber but is unique, because it 1) specifically increases digesta bifidobacteria that have been associated with improved gut health and 2)is completely fermented within the gut. Sources of fiber differ in 2 key characteristics: viscosity and fermentability. Increased viscosity has been associated with increased gut content of virulence factors that are linked with diarrhea. Increased kinetics of fiber fermentation is associated with#changes in microbial profiles and increased metabolite production. Oligosaccharides may be rapidly fermented and thereby influence intestinal microbial profiles and metabolite production. Specific exopolysaccharides from Lactobacillus reuteri may serve as scavenger molecules for pathogenic bacteria, e.g., enterotoxigenic E. coli (ETEC). The ETEC binding to exopolysaccharides may avoid diarrhea initiation by ETEC. Recently, microbial composition was hypothesized to be less important and the focus should be on their combined output of metabolites. Raw materials and prebiotic feed additives both influence kinetics of fermentation and have prebiotic activity. Their kinetics of fermentation should be quantifiedso that it can be included in feed formulation. In conclusion, dietary carbohydrates via their prebiotics activity are part of the solution to remove antibiotics as growth promotant from swine diets.
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