Diet influences the composition and diversity of mucosa-associated microbiota along the longitudinal axis of the pig gastrointestinal tract.

Mucosa-associated microbial populations of the gastrointestinal tract occupy a unique position allowing intimate contact with host epithelial cells lining the gastrointestinal tract. This proximity gives these populations a much higher potential, than the luminal microbiota, in exerting effects on the host. The functional characteristics of the microbiota and the influences of host-derived factors shape the composition and activity of the mucosa-associated bacterial community. We have shown previously that inclusion of a low calorie sweetener, SUCRAM, routinely included in the diet of weaning piglets modulates the composition of luminal-residing gut microbiota, with implications of reducing weaning-related gastrointestinal disorders in pigs. In this study, we have used high throughput Illumina sequencing to characterise the mucosa-associated microbiota along the length of the intestinal tract of weaning piglets and determined the effect of SUCRAM supplementation on mucosa-associated populations. We show that there are clear distinctions in the composition of mucosa-associated microbiota between the small and large intestine, and that there are significant differences in the composition of mucosa-associated compared to luminal microbiota in pig caecum. Dietary supplementation with SUCRAM had a profound effect on mucosa-associated bacterial community structure along the entire length of the intestinal tract. Most notably, there was a substantial reduction in predominant Campylobacter populations proposing that SUCRAM supplementation of swine diet has potential for reducing meat contamination and promoting food safety.