2015/07/29 by DeAnna E. Beasley, Amanda M. Koltz, Joanna E. Lambert +2 · 1 voice · 1 citation
Biochemistry, Genetics and Molecular Biology · Medicine · Veterinary · #Animal Behavior and Welfare Studies #Bacteria #Biology #Carrion #Clostridium difficile and Clostridium perfringens research #Ecology #Gut microbiota and health #Herbivore #Microbial ecology #Microbial population biology #Microbiome #Omnivore #Phylogenetic diversity #Phylogenetics #Predation #Stomach #Trophic level #Vertebrate #Zoology
paper · pdf · doi:10.1371/journal.pone.0134116
openalex publication_date 2015/07/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
Gastric acidity is likely a key factor shaping the diversity and composition of microbial communities found in the vertebrate gut. We conducted a systematic review to test the hypothesis that a key role of the vertebrate stomach is to maintain the gut microbial community by filtering out novel microbial taxa before they pass into the intestines. We propose that species feeding either on carrion or on organisms that are close phylogenetic relatives should require the most restrictive filter (measured as high stomach acidity) as protection from foreign microbes. Conversely, species feeding on a lower trophic level or on food that is distantly related to them (e.g. herbivores) should require the least restrictive filter, as the risk of pathogen exposure is lower. Comparisons of stomach acidity across trophic groups in mammal and bird taxa show that scavengers and carnivores have significantly higher stomach acidities compared to herbivores or carnivores feeding on phylogenetically distant prey such as insects or fish. In addition, we find when stomach acidity varies within species either naturally (with age) or in treatments such as bariatric surgery, the effects on gut bacterial pathogens and communities are in line with our hypothesis that the stomach acts as an ecological filter. Together these results highlight the importance of including measurements of gastric pH when investigating gut microbial dynamics within and across species.