Gut microbiota resilience in horse athletes following holidays out to pasture

Núria Mach,Marie-Pierre Moisan,Léa Lansade,Aline Foury,Alice Ruet,David Bars-Cortina,Sophie Dhorne-Pollet

doi:10.1038/s41598-021-84497-y

Abstract

Elite horse athletes that live in individual boxes and train and compete for hours experience long-term physical and mental stress that compromises animal welfare and alters the gut microbiota. We therefore assessed if a temporary period out to pasture with conspecifics could improve animal welfare and in turn, favorably affect intestinal microbiota composition. A total of 27 athletes were monitored before and after a period of 1.5 months out to pasture, and their fecal microbiota and behavior profiles were compared to those of 18 horses kept in individual boxes. The overall diversity and microbiota composition of pasture and control individuals were temporally similar, suggesting resilience to environmental challenges. However, pasture exposure induced an increase in Ruminococcus and Coprococcus that lasted 1-month after the return to individual boxes, which may have promoted beneficial effects on health and welfare. Associations between the gut microbiota composition and behavior indicating poor welfare were established. Furthermore, withdrawn behavior was associated with the relative abundances of Lachnospiraceae AC2044 group and Clostridiales family XIII. Both accommodate a large part of butyrate-producing bacterial genera. While we cannot infer causality within this study, arguably, these findings suggest that management practices maintained over a longer period of time may moderate the behavior link to the gut ecosystem beyond its resilience potential.

Highlights

The role of gut microbiota on behavioral changes has been posited by Destrez et al.[11], who observed that the concentration of amylolytic bacteria and the abundance of Succinivibrionaceae positively correlated to bowing following a low fiber but high starch diet
While formal proof is missing in horses, a prevailing hypothesis is that the impact of the long-term physical and emotional stress in elite athletes individually housed could be alleviated by allowing individuals to benefit from a temporary period in a more natural environment, such as out to pasture with c onspecifics[19]
R. flavefaciens were consistently less abundant in individuals expressing withdrawn posture compared to non-expressors (Supplementary Table S7). This is the first study to assess if a temporary holiday on pasture modifies the gut microbiota and the occurrence of behaviors related to a compromised welfare state in elite horses

Summary

Introduction

Enteric short-chain fatty acids (SCFAs), the major class of metabolites produced from bacterial fermentation of non-digestible carbohydrates, are widely thought to mediate the relationship between the gut microbiota and the brain Neurotransmitters such as ɣ-amino butyric acid (GABA), dopamine and serotonin, stress hormones and immune system modulators are thought to play at least a partial role in this molecular interchange[17,18]. While formal proof is missing in horses, a prevailing hypothesis is that the impact of the long-term physical and emotional stress in elite athletes individually housed could be alleviated by allowing individuals to benefit from a temporary period in a more natural environment, such as out to pasture with c onspecifics[19] This sudden and single short-term exposition to a more natural environment could be beneficial for the gut microbiota (e.g., increasing diversity, reducing abundance of proinflammatory taxa and rare pathobionts and increasing abundance of putatively beneficial taxa). By jointly characterizing the composition of gut microbiota and the behavioral indicators of poor welfare, we aimed at providing a functional readout of microbial activity and improve our understanding of the gut-brain axis in athletes

Methods

Results

Conclusion