Abstract
Background: The influences of infant gastrointestinal (GI) microbiome on intestinal and brain development is unclear. Human milk (HM) is associated with beneficial immune and cognitive development compared with infant formula (IF). Feeding exposures (HM or IF) may influence GI microbiome and affect infant intestinal and brain development. This study aimed to determine the effects of infant feeding groups (HM vs. IF) on GI microbiome composition, intestinal inflammation, brain oligodendrocyte maturation, and to assess relationships therein. Methods: Six pairs of piglets received HM or IF from 2 to 30 days of life. Fecal samples were collected weekly and GI regions (jejunum, ileum, and colon) and brains were harvested at necropsy. Fecal microbiome composition was determined using 16S ribosomal RNA (16S rRNA) sequencing. Intestinal inflammation was assessed via intestinal interleukin (IL)-1β, IL-8, IL-10, and tumor necrosis factor (TNF)-α, and fecal calprotectin quantification. Neurodevelopment was evaluated by quantifying mature and immature oligodendrocytes from gray and white matter. Results: Beta-diversity of the bacterial community differed between feeding groups (p<0.002) and over time (p=0.001). Various highly abundant genera were associated with changes over time (p<0.05) and Escherichia-Shigella was associated with feeding group by time interactions (p<0.05). No differences were found in intestinal inflammatory markers nor oligodendrocytes between feeding groups. However, various inflammatory markers and relatively highly abundant genera were significantly associated. Conclusions: Piglet fecal bacterial compositions differ over time and by feeding group, and several relatively highly abundant genera are associated with intestinal inflammatory markers. Future research should investigate the mechanisms underlying these relationships.