Enhanced tameness by Limosilactobacillus reuteri from gut microbiota of selectively bred mice

Domestication alters animal behaviour, primarily their tameness. We examine the effect of gut bacteria on tameness in mice. We examined gut microbiota in mice bred for active tameness by analysing faecal samples from 80 mice through shotgun metagenomic analysis. Selection for tameness did not substantially alter the gut microbiota’s taxonomic or functional diversity. However, we observed an increased abundance of Limosilactobacillus reuteri in the selected groups and higher pyruvate levels in their plasma. We isolated L. reuteri strains secreting extracellular pyruvate, and administrated the cultured bacteria through drinking water. Mice treated with L. reuteri showed abundance of bacteria in the gut and a high level of active tameness compared to the control. This study elucidates the potential role of L. reuteri in the domestication process.