Bacterial communities of the uterus and rumen during heifer development with protein supplementation

Authors: AULT-SEAY, TAYLOR - University Of Tennessee; BRANDT, KIERNAN - University Of Tennessee; HENNIGER, MADISON - University Of Tennessee; PAYTON, REBECCA - University Of Tennessee; MATHEW, DANIEL - University Of Tennessee; MOOREY, SARAH - University Of Tennessee; SCHRICK, F. - University Of Tennessee; POHLER, KY - Texas A&M University; Smith, Timothy - Tim; RHINEHART, JUSTIN - University Of Tennessee; SCHNEIDER, LIESEL - University Of Tennessee; MCLEAN, KYLE - University Of Tennessee; MYER, PHILLIP - University Of Tennessee

Submitted to: Frontiers in Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/13/2022
Publication Date: 7/7/2022
Citation: Ault-Seay, T.B., Brandt, K.J., Henniger, M.T., Payton, R.R., Mathew, D.J., Moorey, S.E., Schrick, F.N., Pohler, K.G., Smith, T.P.L., Rhinehart, J.D., Schneider, L.G., McLean, K.J., Myer, P.R. 2022. Bacterial communities of the uterus and rumen during heifer development with protein supplementation. Frontiers in Animal Science. 3. Article 903909. https://doi.org/10.3389/fanim.2022.903909.
DOI: https://doi.org/10.3389/fanim.2022.903909

Interpretive Summary: The uterus of cattle had long been thought to be a sterile environment and the presence of bacteria considered an undesirable pathogenic state. However, more recent studies have determined that the uterus harbors a distinct population of bacteria that can positively affect uterine health and fertility. The rumen of cattle are specialized to break down the components of plants into digestible materials for the nutrition of the animal, which is likewise substantially affected by the bacterial populations, or "microbiome", present in this organ. Little is known about the changes that occur in the microbiomes of uterus or rumen during heifer development, although they may have important effects on animal health and reproductive fitness. Different management strategies may impact the development of healthy microbiomes conducive to animal productivity, so this study examined microbiomes of these organs during heifer development from weaning to first breeding under three diets consisting of increasing crude protein supplementation. The study observed relative stability of the overall diversity of the bacterial populations, but identified specific changes associated with the level of supplementation. The data provide an initial glimpse into the interaction of diet and the microbiomes of the rumen and uterus in heifers as a basis for future studies into optimizing management for increasing probability of developing favorable bacterial populations.

Technical Abstract: Bacterial communities play major roles in rumen and uterine function toward optimal animal performance and may be affected by changes occurring during heifer development such as nutritional supplementation for optimal growth and the attainment of puberty. The effect of different levels of protein supplementation on ruminal and uterine bacterial communities following weaning was examined through first breeding of heifers. Angus heifers (n = 39) were blocked by initial body weight (BW) and randomly assigned to one of three 163-day (d) crude protein (CP) supplementation diets including control (10% CP, n = 14), 20% CP (n = 11), or 40% CP (n = 14) treatment groups. Growth and development were monitored by body weight, with blood progesterone concentration determined every 14 d to determine pubertal status. Uterine flush and rumen fluid were collected on d 56, 112, and 163 relative to the start of supplementation. Bacterial DNA was extracted from fluid samples, the V1–V3 hypervariable region of the 16S rRNA gene was amplified, and amplicons were sequenced then processed in R 4.1. Statistical analyses were performed in SAS 9.4 with a GLIMMIX procedure utilizing fixed effects of protein, month, pubertal status, and interactions, with random effects including BW, interaction of BW and protein, and heifer within the interaction, and repeated measures of day. In the uterus, pubertal status and day of supplementation affected the observed amplicon sequence variants (ASVs) and led to clustering of samples in a principal coordinate analysis (PCoA; P < 0.05), but no effect of protein supplementation was observed. Ruminal samples clustered in PCoA (P = 0.001), and observed ASVs were impacted over time (P < 0.0001), but no effect of protein supplementation was detected. In contrast, protein supplementation, pubertal status, and day of supplementation affected the abundance of multiple phyla and genera in the uterus and rumen (P < 0.05). Temporal and pubertal status effects on the heifer’s uterine bacterial communities potentially indicate a maturing uterine microbiome. Protein supplementation did not impact microbial diversity measures but did affect the abundance of individual bacterial phyla and genera that may provide future opportunities to manipulate bacterial community composition and maximize productivity.