Baumgaertner, F. | bioRxiv Science

bioRxiv2023

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. IMPORTANCEIncreased appreciation of maternal nutrition and microbiomes 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.

microbiology↗

bioRxiv2021

The nasopharyngeal, ruminal, and vaginal microbiota and the core taxa shared across these microbiomes in virgin yearling heifers exposed to divergent in utero nutrition during their first trimester of gestation and in pregnant beef heifers in response to mineral supplementation

Emerging evidence has indicated that microbial transmission from the bovine dam to her fetus may take place before birth, and that the maternal microbiota during pregnancy modulates programming of fetal metabolic and nervous system development, highlighting the potential and extended role of the maternal microbiome in calf health and development. In the present study, we characterized the nasopharyngeal, ruminal and vaginal microbiota from two cohorts of beef heifers managed at the same location: 1) virgin yearling heifers (9 months old) born from dams received gestational diets which resulted in low (LG, n = 22) or medium (MG, n = 23) weight gain during the first 84 days of gestation; and 2) pregnant replacement heifers that received a vitamin and mineral supplement (VTM, n = 17) or not (Control, n = 15) during the first 6 months of gestation. Nasopharyngeal and vaginal swabs as well as ruminal fluid were collected from both cohorts and the microbiota of each sample was assessed using 16S rRNA gene sequencing. In addition to the comparison between treatment groups within each cohort, the similarity of the microbiota of the three sample types were evaluated, and shared taxa amongst these communities were identified. The bacterial genera present in the rumen and vagina that can influence methanogenic archaeal genera were predicted using a stepwise-selected generalized linear mixed model. No significant difference was observed in the alpha and beta diversity in any of the nasopharyngeal, ruminal and vaginal microbiota between LG and MG offspring virgin heifers, or between the control and VTM pregnant heifers (p > 0.05). Subtle compositional changes in the vaginal microbiota in yearling heifers, and in the nasopharyngeal and ruminal microbiota of pregnant heifers were detected in response to treatments. Forty-one archaeal and bacterial OTUs were shared by over 60% of all samples from both virgin and pregnant heifers. Two taxa within the Methanobrevibacter genus were identified as core taxa and this genus was more relatively abundant in pregnant heifers compared to virgin heifers. Among the 25 top genera, Prevotella and Prevotella UCG-003 (negative) and Christensenellaceae R-7 group (positive) were predicted to have a significant effect on ruminal Methanobrevibacter spp. The results of this study indicate that there is little impact of divergent gestational nutrition during the first trimester on the calf microbiome at 9 months postnatal, and that VTM supplementation during pregnancy may not alter the maternal microbiome. This study provides evidence that there are several microbial taxa, including methanogenic archaea, that are shared across the respiratory, gastrointestinal, and reproductive tracts, suggesting the need for a holistic evaluation of the bovine microbiota when considering potential maternal sources for seeding calves with pioneer microbiota.

microbiology↗