Abstract
Emerging knowledge shows the importance of early life events in programming the intestinal mucosal immune system and development of the intestinal barrier function. These processes depend heavily on close interactions between gut microbiota and host cells in the intestinal mucosa. In turn, development of the intestinal microbiota is largely dependent on available nutrients required for the specific microbial community structures to expand. It is currently not known what the specificities are of intestinal microbial community structures in relation to the programming of the intestinal mucosal immune system and development of the intestinal barrier function. The objective of the present study was to investigate the effects of a nutritional intervention on intestinal development of suckling piglets by daily oral administration of fructooligosaccharides (FOS) over a period of 12 d (days 2-14 of age). At the microbiota community level, a clear "bifidogenic" effect of the FOS administration was observed in the colon digesta at day 14. The former, however, did not translate into significant changes of local gene expression in the colonic mucosa. In the jejunum, significant changes were observed for microbiota composition at day 14, and microbiota diversity at day 25. In addition, significant differentially expressed gene sets in mucosal tissues of the jejunum were identified at both days 14 and 25 of age. At the age of 14 d, a lower activity of cell cycle-related processes and a higher activity of extracellular matrix processes were observed in the jejunal mucosa of piglets supplemented with FOS compared with control piglets. At day 25, the lower activity of immune-related processes in jejunal tissue was seen in piglets supplemented with FOS. Villi height and crypt depth in the jejunum were significantly different at day 25 between the experimental and control groups, where piglets supplemented with FOS had greater villi and deeper crypts. We conclude that oral FOS administration during the early suckling period of piglets had significant bifidogenic effects on the microbiota in the colon and on gene expression in the jejunal mucosa by thus far unknown mechanisms.