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Nutritional Microbiology/Microbiome/Microbiome Nutrition (Poster Session)

(P19-012-25) Obesity and Dietary Soy Protein With Different Isoflavone Levels Alter Fecal Microbial Composition in Zucker Rats Over 9- and 18-Week Periods

Sunday, June 1, 2025
11:45 AM - 12:45 PM ET
Location: Poster Board B-54

    Presenting Author(s)

  • Reza Hakkak, PhD

    Professor
    University of Arkansas for Medical Sciences
    Little Rock, Arkansas, United States

    • Co-Author(s)

  • WL

    Wei Li, PhD

    Assistant Professor
    University of Arkansas for Medical Sciences
    Little Rock, Arkansas, United States

  • CR

    Christopher Randolph

    Arkansas Children's Research Institute, United States

  • MR

    Micheal S. Robeson, II

    University of Arkansas for Medical Sciences, United States

Disclosure(s):
Reza Hakkak, PhD: No relevant financial relationship(s) with ineligible companies to disclose.
Wei Li, PhD: No relevant financial relationship(s) with ineligible companies to disclose.


Objectives: To characterize the effects of obesity and dietary soy protein with different isoflavone levels on microbial composition in Zucker rats over short- and long-terms. We hypothesized that both obesity and soy diet components (i.e. soy protein and isoflavone) would alter fecal microbial composition.

Methods: Six-week-old male obese (fa/fa) Zucker rats were randomly assigned to receive three types of diet (6-7 rats per group) with casein (CAS) as a control, soy protein concentrate with low isoflavone (SPC-LIF), or soy protein concentrate with high isoflavone (SPC-HIF) as the protein source. The SPC-LIF and SPC-HIF diets had 0.154 mg and 2.153 mg total isoflavone/g protein, respectively. Rats were housed individually and had ad libitum access to water and diets. Fecal samples were collected at 9 and 18 weeks. DNA from fecal samples were extracted and the V4 regions of 16S rRNA gene were sequenced. QIIME 2 was used to prepare and analyze the data. Amplicon sequence variants were generated via DADA2, and classified using the SILVA (v138.2) databases curated by RESCRIPt. Data was subsequently analyzed using eta-diversity (Weighted UniFrac, Unweighted UniFrac, Bray-Curtis, & Jaccard), and differential abundance (ANCOM-BC) analyses.

Results: Both obesity and dietary soy protein (i.e. SPC-LIF and SPC-HIF) altered fecal microbial beta-diversity. Generally, all beta diversity metrics supported significant differences across obesity and soy protein diets (SPC-LIF and SPC-HIF). ANCOM-BC detected differential enrichment of microbial features of Zucker rats at both 9- and 18-weeks. Compared to the CAS control, the dietary effect was more pronounced in the SPC-HIF groups at both time points. These significant microbial features were visualized via a clustermap and show segregation of samples based on obesity status and dietary treatments.

Conclusions: Lean and obese Zucker rats had different fecal microbial compositions. Dietary soy protein and isoflavones had both short-term (9-week) and long-term (18-week) effects on fecal microbial profile in lean and obese rats.

Funding Sources: This project was supported by USDA grant number 2020-67017-30841 to RH.