Alteration to Gastrointestinal Microbial Communities Associated with Increasing Fiber Digestibility

Distillers dried grains with solubles (DDGS) is a byproduct of distillation. Its increased availability has led to research into overcoming the nutritional limitations of its high non-starch polysaccharide (NSP) content for use in monogastric animal feed. The purpose of this study was to examine the effects of two factors (the inclusion of DDGS and/or inclusion of a carbohydrase mixture) on the richness and abundance of swine gastrointestinal bacteria. The carbohydrase mixture was expected to aid digestion, leading to increased nutritional availability for the host while simultaneously shifting dominant communities within the gut microbiome.

Ileal cannulated pigs (n = 8, BW = 64.3 +/-0.5 kg) were allotted to 4 dietary treatments in a replicated 4 x 4 Latin square design. Treatments resulted in changes to bacterial richness, and diets containing DDGS increased the 16S rDNA abundance of members of Bacteroides (P < 0.0001), Ruminococcus (P < 0.0001), the Clostridium coccoides group (P <0.0001), and the Clostridium leptum subgroup (P = 0.005). Significant interactions between diet and carbohydrases were determined for total bacteria in the ileal digesta (P = 0.01) and feces (P = 0.02), Bacteroides (P = 0.003), and the Clostrdium leptum subgroup (P = 0.03). The DDGS diet with the inclusion of the carbohydrases was able to maintain, or increase the abundance of fiber degrading bacteria while theoretically increasing nutrition for the host.