Intestinal Methanobrevibacter smithii but not total bacteria is related to diet‐induced weight gain in rats12. (25th May 2013)

• Record Type: Journal Article
• Authors: Mathur, Ruchi; Kim, Gene; Morales, Walter; Sung, Jaekyu; Rooks, Emily; Pokkunuri, Venkata; Weitsman, Stacy; Barlow, Gillian M.; Chang, Christopher; Pimentel, Mark
• Is Part Of: Obesity. Volume 21:Number 4(2013:Apr.)
• Page Start: 748
• Page End: 754
• Publication Date: 2013-05-25
• Subjects: Obesity -- Periodicals; 616.398005
• DOI: 10.1002/oby.20277
• Languages: English
• ISSNs: 1930-7381

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <sec id="abs1-0" sec-type="section"> <p>It is increasingly understood that gastrointestinal (GI) methanogens, including <italic>Methanobrevibacter smithii, </italic> influence host metabolism.</p> </sec> <sec id="abs1-1" sec-type="section"> <title>Objective:</title> <p>Therefore, we compared <italic>M. smithii</italic> colonization and weight gain in a rat model under different dietary conditions.</p> </sec> <sec id="abs1-2" sec-type="section"> <title>Design and Methods:</title> <p>Sprague‐Dawley rats were inoculated with <italic>M. smithii</italic> or vehicle (<italic>N</italic> = 10/group), fed normal chow until day 112 postinoculation, high‐fat chow until day 182, then normal chow until day 253. Thereafter, five rats from each group were fed high‐fat and normal chow until euthanasia.</p> </sec> <sec id="abs1-3" sec-type="section"> <title>Results:</title> <p>Both groups exhibited <italic>M. smithii</italic> colonization, which increased following inoculation only for the first 9 days. Change to high‐fat chow correlated with significant increases in weight (<italic>P</italic> < 0.00001) and stool <italic>M. smithii</italic> (<italic>P</italic> < 0.01) in all rats, with stool <italic>M. smithi</italic> decreasing on return to normal chow. Rats switched back to high‐fat on day 253 further increased weight (<italic>P</italic> < 0.001) and stool <italic>M. smithii</italic> (<italic>P</italic> = 0.039). Euthanasia revealed all animals had higher <italic>M. smithii, </italic> but not total bacteria, in the small intestine than in the colon. Rats switched back to high‐fat chow had higher <italic>M. smithii</italic> levels in the duodenum, ileum, and cecum than those fed normal chow; total bacteria did not differ in any bowel segment. Rats which gained more weight had more bowel segments colonized, and the lowest weight recorded was in a rat on high‐fat chow which had minimal <italic>M. smithii</italic> colonization.</p> </sec> <sec id="abs1-4" sec-type="section"> <title>Conclusions:</title> <p>We conclude that <italic>M. smithii</italic> colonization occurs in the small bowel as well as in the colon, and that the level and extent of <italic>M. smithii</italic> colonization is predictive of degree of weight gain in this animal model.</p> </sec> </abstract>