Gut Microbiota Represent a Major Thermogenic Biomass. Function (Oxf) 2021;2(3):zqab019
Date
05/04/2021Pubmed ID
33939772Pubmed Central ID
PMC8055641DOI
10.1093/function/zqab019Scopus ID
2-s2.0-85114762228 (requires institutional sign-in at Scopus site) 18 CitationsAbstract
Evidence supports various roles for microbial metabolites in the control of multiple aspects of host energy flux including feeding behaviors, digestive efficiency, and energy expenditure, but few studies have quantified the energy utilization of the biomass of the gut microbiota itself. Because gut microbiota exist in an anoxic environment, energy flux is expected to be anaerobic; unfortunately, commonly utilized O2/CO2 respirometry-based approaches are unable to detect anaerobic energy flux. To quantify the contribution of the gut microbial biomass to whole-animal energy flux, we examined the effect of surgical reduction of gut biomass in C57BL/6J mice via cecectomy and assessed energy expenditure using methods sensitive to anaerobic flux, including bomb and direct calorimetry. First, we determined that cecectomy caused an acceleration of weight gain over several months due to a reduction in combined total host plus microbial energy expenditure, as reflected by an increase in energy efficiency (ie, weight gained per calorie absorbed). Second, we determined that under general anesthesia, cecectomy caused immediate changes in heat dissipation that were significantly modified by short-term pretreatment with dietary or pharmaceutical interventions known to modify the microbiome, and confirmed that these effects were undetectable by respirometry. We conclude that while the cecum only contributes approximately 1% of body mass in the mouse, this organ contributes roughly 8% of total resting energy expenditure, that this contribution is predominantly anaerobic, and that the composition and abundance of the cecal microbial contents can significantly alter its contribution to energy flux.
Author List
Riedl RA, Burnett CML, Pearson NA, Reho JJ, Mokadem M, Edwards RA, Kindel TL, Kirby JR, Grobe JLAuthors
Justin L. Grobe PhD Professor in the Physiology department at Medical College of WisconsinTammy Lyn Kindel MD, PhD Associate Professor in the Surgery department at Medical College of Wisconsin
John Kirby PhD Chair, Center Associate Director, Professor in the Microbiology and Immunology department at Medical College of Wisconsin
John J. Reho Research Scientist II in the Physiology department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
AnimalsBiomass
Gastrointestinal Microbiome
Mice
Mice, Inbred C57BL
Microbiota
Weight Gain
