Biogeographical Differences in the Influence of Maternal Microbial Sources on the Early Successional Development of the Bovine Neonatal Gastrointestinal tract

Abstract

The impact of maternal microbial influences on the early choreography of the neonatal calf microbiome were investigated. Luminal content and mucosal scraping samples were collected from ten locations in the calf gastrointestinal tract (GIT) over the first 21 days of life, along with postpartum maternal colostrum, udder skin, and vaginal scrapings. Microbiota were found to vary by anatomical location, between the lumen and mucosa at each GIT location, and differentially enriched for maternal vaginal, skin, and colostral microbiota. Most calf sample sites exhibited a gradual increase in α-diversity over the 21 days beginning the first few days after birth. The relative abundance of Firmicutes was greater in the proximal GIT, while Bacteroidetes were greater in the distal GIT. Proteobacteria exhibited greater relative abundances in mucosal scrapings relative to luminal content. Forty-six percent of calf luminal microbes and 41% of mucosal microbes were observed in at-least one maternal source, with the majority being shared with microbes on the skin of the udder. The vaginal microbiota were found to harbor and uniquely share many common and well-described fibrolytic rumen bacteria, as well as methanogenic archaea, potentially indicating a role for the vagina in populating the developing rumen and reticulum with microbes important to the nutrition of the adult animal.

Figure 1

Mean bacterial diversity at the phylum level for maternal and calf lumen (A) and mucosal (B) samples.

Figure 2

Biogeographical Distribution of Microbial Genera. The percent abundances of the major microbial genera distributed throughout the luminal (A) and mucosal (B) regions of each GIT location are shown for each age group. Genera are color coded as shown in the figure key as shades of green (Firmicutes), Orange-red (Bacteroidetes), purple (Proteobacteria), blue (other phyla), or grey (Euryarcheota).

Figure 3

Non-metric multidimensional scaling (nMDS) plot of Bray-Curtis Relationships. Samples are colored by anatomical location, and shaded to reflect mucosal (open) and luminal (closed) samples Maternal microbiota are shown with an asterisk.

Figure 4

Proportion of OTUs shared with maternal sources across GIT locations and between mucosa and lumen with age. Jejunum proportions are averages of the proximal, medial, and distal region.