Abstract P478: Short-Term Voluntary Exercise Significantly Influences the Diet-Induced Changes in Cecal Microbial Content in Male Mice

Abstract

Two leading environmental factors that influence the overall health of humans are diet and physical exercise. However, it is still unclear how these factors influence health and disease susceptibility. Both diet and exercise have been shown to modulate the microbial flora that may significantly influence health and disease; however, it is unclear if diet modulates the effects of exercise on gut microflora. Therefore, this study aimed to determine how diet and exercise modulate the microbial content of the mouse cecum. Male, weanling, C57Bl/6 mice were randomly assigned to receive one of three diets ad libitum: standard laboratory chow, AIN93-G, and our novel Americanized diet (AD). Within each diet, mice were then assigned to a voluntary exercise regimen (wheel access, 16-hours per day, 3-days per week) or a control sedentary group (individually housed in cage without wheel for the same duration and frequency). After 2-weeks of exercise, mice were euthanized and cecal microbial content was determined by16S rDNA sequencing and RT-PCR for Firmicutes (FIRM), Bifidobacterium (GBIFD), Lactobacillus (LB) , and Bacteroides (BACT). Data were analyzed using GLM Procedures in SPSS with significance determined at P<0.05. Pilot results found that diet, exercise, and their interaction significantly influenced FIRM expression. Mice fed the standard chow diet had the lowest expression of FIRM , which was significantly lower than mice fed AIN (P<0.001) and AD (P=0.001). Exercise caused a significant decrease (P<0.001) in FIRM presence, especially in mice fed AIN and AD. Diet and exercise also significantly influenced GBIFD , with mice fed AIN having significantly more GBIFD than mice fed chow and AD (P<0.001 for both). Exercise also caused a significant reduction (P=0.016) in GBIFD , and a reduction in LB expression in mice fed chow and AD, but not AIN (P=0.03). The results of this study highlight how two key aspects of lifestyle, diet and exercise, independently and additively influence the gastrointestinal flora in a preclinical mouse model. Additional studies are needed to validate these findings and determine their physiological significance.