Whole-body Microbiota of Newborn Calves and Their Response to Prenatal Vitamin and Mineral Supplementation

Here, we investigated whether initial microbial colonization at seven different anatomical locations in newborn calves and their blood cytokines are influenced by prenatal vitamin and mineral (VTM) supplementation. Samples were collected from the hoof, liver, lung, nasal cavity, eye, rumen (tissue and fluid), and vagina of beef calves that were born from dams that received diets with or without VTM supplementation throughout gestation (n=7/group). Calves were separated from their dams immediately after birth and fed colostrum and milk replacer until euthanasia at 30 h post-initial colostrum feeding. The microbiota of all samples was assessed using 16S rRNA gene sequencing and qPCR. 15 cytokines and chemokines were quantified in their serum. The hoof, ocular, liver, respiratory, and reproductive sites of newborn calves were colonized by site-specific microbiota that differed from that of the rumen (0.64 ≥ R2 ≥ 0.12, P ≤ 0.003). Only the ruminal fluid microbiota was differed by on prenatal VTM supplementation (P<0.01 Differences (P<0.05) were detected in microbial richness (vagina), diversity (ruminal tissue and fluid, eye), composition at the phylum and genus level (ruminal tissue and fluid, and vagina), and total bacterial abundance (ocular and vagina) between VTM and control calves. The cytokine IP-10 was higher (P=0.02) in VTM calves. Overall, our results suggest that despite immediate separation from the dam upon birth, whole-body of 32-h old calves are colonized by relatively rich, diverse and site-specific bacterial communities, and that initial microbial colonization of the rumen, vagina and oculus seem to be influenced by the prenatal VTM supplementation. IMPORTANCE Increased appreciation of maternal nutrition and microbiome’s involvement in developmental programming and evidence supporting in utero microbial colonization highlight that maternal nutrition factors could impact offspring microbial colonization. Here, we investigated whether initial microbial colonization in any of 7 different anatomical sites of newborn calves was influenced by maternal vitamin and mineral (VTM) supplementation. We identified changes in ruminal, vaginal, and ocular microbiota in newborn calves in response to prenatal VTM supplementation. We provided a “holistic” view on the whole-body calf microbiota. Our data was obtained from calves of the same sex and age, and who were immediately separated from dams, and hence provides novel insights on taxonomic composition of initial bacterial microbiota colonization in those anatomical sites examined. Combined, this study provides direction for future work targeting the manipulation of early life microbiome via alteration of maternal nutrition and harnessing early life microbiota for improved cattle health and production.