Investigating the Effects of a Phytobiotics-Based Product on the Fecal Bacterial Microbiome of Weaned Pigs

SIMPLE SUMMARY: Maintaining gut health during the weaning period remains a major challenge for swine producers. Phytobiotics, which are plant-derived bioactive products for use as supplements in food animals, have shown great promise in helping to stabilize the gut environment of weaned pigs, but their mechanisms of action remain unclear. To determine if the positive impact of phytobiotics on gut health may be by influencing the symbiotic bacteria that inhabit the gut of young pigs, this report describes a comparison between fecal bacterial populations of weaned pigs supplemented with a commercial phytobiotic product for seven days to those of untreated pigs. Together, the results indicate that phytobiotic supplementation may provide a favorable environment for both lactate-producing and lactate-utilizing bacteria. ABSTRACT: The transition to a solid diet, as well as environmental and social stress, have a direct impact on swine gut physiology during weaning, affecting host gastrointestinal functions, as well as resident symbiotic microbial communities. While plant-derived bioactive products, such as phytobiotics, have shown great potential to mitigate these challenges, providing benefits such as antimicrobial, antioxidant, and anti-inflammatory activities, their mechanisms of action remain largely unexplored. To gain more insight, a 21 day trial is conducted to investigate the effects of LiveXtract, a commercial plant-based product, using fecal samples as a proxy for gut bacteria in weaned pigs. High-throughput sequencing of amplicons targeting the V1–V3 region of the 16S rRNA gene is used to determine bacterial composition at days 1 (pre-treatment), 4, 10, and 21 postweaning. Our results show that Lactobacillaceae and Peptostreptococcaceae are both higher in the supplemented group at D4 (p < 0.05), while Streptococcaceae are significantly lower in the treated group at D10 and D21. At D10, Erysipelotrichaceae are lower, and Veillonellaceae are higher in the treated samples than the control group (p < 0.05). Of the thirteen abundant Operational Taxonomic Units (OTUs) that have different representation between treated and control pigs (p < 0.05), six are predicted to be lactate producers (affiliation to Lactobacillus or Streptococcus), and one is predicted to be a lactate utilizer, based on its high identity to Megasphaera elsdenii. Together, these data suggest that phytobiotics may provide a favorable metabolic equilibrium between lactate production and utilization. Lactate is considered a critical microbial end product in gut environments, as it can inhibit pathogens or be metabolized to propionate for utilization by host cells.