TAKE A WALK ON THE (RE)WILD SIDE: FEEDING BEHAVIOR AND IMMUNITY IN REWILDED MICE

Abstract

The environmental context in which an individual lives can have a profound impact on immune phenotype, feeding behavior and diet, potentially by way of the microbiome. Rewilded mice, which are lab-bred mice released into outdoor enclosures, provide a good model for studying the environmental impact on immune systems, because we are able to control genotypes while still allowing for natural exposure to pathogens, and thus the development of a diverse gut microbial community and acquired immune system. This study investigates how changes in the feeding behavior and microbiome diversity of rewilded mice may impact immune phenotype, using immunoglobulin and relative immune cell abundances as immune measures. Additionally, we consider how change in body mass and exercise may begin to fit into the complex relationship between feeding behavior and immunity. IgM antibody levels were significantly higher in rewilded mice than laboratory mice, while IgG antibody levels were lower. We show that neither feeder behavior nor Shannon microbiome diversity appears to significantly impact immune cell abundances or IgG/IgM levels. We also show the role that genotype can play in modulating environment-phenotype interactions through its effect on the relationship between feeding behavior and T/B Cell abundances. This suggests the need to further explore the mechanisms behind environment/immune phenotype relationships, such as the role of genetics or resource allocation trade-offs. Future research could also consider other measures of immune phenotype as well as trade-offs between infection tolerance and resistance.