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Kidney Week

Abstract: PO2017

Diet Has a Stronger Impact on the Gut Microbiota Than Kidney Function in Rats with Moderate CKD

Session Information

Category: Health Maintenance, Nutrition, and Metabolism

  • 1300 Health Maintenance, Nutrition, and Metabolism

Authors

  • Biruete, Annabel, Indiana University School of Medicine, Indianapolis, Indiana, United States
  • Cross, Tzu-Wen L., Purdue University, West Lafayette, Indiana, United States
  • Lindemann, Stephen R., Purdue University, West Lafayette, Indiana, United States
  • Swanson, Kelly, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States
  • Chen, Neal X., Indiana University School of Medicine, Indianapolis, Indiana, United States
  • Moe, Sharon M., Indiana University School of Medicine, Indianapolis, Indiana, United States
Background

Diet and CKD have been shown to alter the gut microbiota. However, whether diet or kidney function plays a stronger role in the gut microbiota in moderate CKD is not well established. We assessed the effects of two diets on the gut microbiota in rats with moderate CKD.

Methods

Cy/+ rats (CKD) and normal littermates (NL) consumed an autoclaved grain-based diet containing 0.7% phosphorus (0.3% phytate-bound) and 3.5% crude fiber from birth. At 17-wk-old, half of the animals were maintained on the same diet (Grain) and the other half switched to a semi-purified casein-based diet containing 0.7% phosphorus (0% phytate-bound, 0.6% phosphate additives) and 5% non-fermentable cellulose (Casein) until 28-wk-old (n=8-10 rats/group). DNA was extracted from cecal and fecal samples collected at euthanasia, the V4 region of the 16S rRNA gene was sequenced via Illumina MiSeq, and data were analyzed using QIIME2 and LEfSe.

Results

Intestinal microbial a-diversity, or diversity within a sample, was significantly greater in rats fed the grain diet compared to casein diet regardless of kidney function. Diet and kidney function both had significant impacts on microbial β-diversity (diversity between samples), but diet explained a larger portion of the observed variability (27%) than kidney function (11.5%). Consumption of the grain-based diet increased many genera with short-chain fatty acid (SCFA) producing capacity, including Bifidobacterium, Ruminococcus, Roseburia, and Prevotella than the casein diet. Whereas the casein diet drove greater Bacteroides abundance that can metabolize tryptophan to indoles, which may exacerbate the formation of uremic toxins. Notably, the casein diet led to a greater abundance of Bilophila in NL rats and greater Allistipes in CKD. Both of these taxa have been suggested to drive the pathogenesis of inflammatory bowel disease. Additionally, CKD rats fed the casein diet had a higher relative abundance of Akkermansia, which has been shown to be greater in fiber-free or low fiber interventions, as it may degrade the mucus layer.

Conclusion

In rats with moderate CKD, diet had a stronger effect on diversity and gut microbial taxonomic differences than kidney function. Particularly, those fed the grain-based diet had higher bacterial genera known to produce SCFA.

Funding

  • Other NIH Support