Overview
Mice exposed to K2Cr2O7 at 75 mg/kg exhibited marked gut microbial dysbiosis, with reduced alpha diversity (Chao1 and Shannon indices significantly lower), decreased beneficial taxa, and increased pathogenic bacteria including Escherichia_Shigella (rising from 10.71% in controls to 57.75% under Cr exposure). Administration of seaweed polysaccharide at 200 mg/kg restored gut microbial diversity and partially reversed compositional shifts, restoring Bacteroidota and Firmicutes abundances toward control levels. The study provides mechanistic grounding for food-chain chromium exposure as a gut microbiome disruptor and identifies a dietary intervention candidate.
Key numbers
- Control vs Cr(VI) group Chao1: 170.75 ± 15.79 vs 87.00 ± 9.55 (p = 0.00029)
- Control vs Cr(VI) group Shannon: 4.64 ± 0.68 vs 2.64 ± 0.64 (p = 0.0055)
- Control vs Cr(VI) group Simpson: 0.88 ± 0.060 vs 0.63 ± 0.15 (p = 0.035)
- Escherichia_Shigella relative abundance: control 10.71%, Cr group 57.75%, SP treatment group 33.45%
- Total OTUs: 358 (control 298, Cr 182, SP 269)
- Cr(VI) dose: 75 mg/kg K2Cr2O7 by compulsory gavage; seaweed polysaccharide dose: 200 mg/kg; duration 29 days
- 16S amplicon sequencing V3/V4 regions, MiSeq 2×300 bp; 502,400 valid sequences from 735,152 raw reads
Methods (brief)
Mouse gavage experiment. Colon contents collected at endpoint; DNA extracted with QIAamp DNA Mini Kit. 16S rRNA amplicon sequencing (V3/V4) on Illumina MiSeq; OTUs clustered at 97% similarity. Alpha diversity (Chao1, ACE, Shannon, Simpson), PCoA, Metastats differential analysis, LEfSe. No direct food-matrix metal measurements; the Cr(VI) exposure route is gavage, not dietary.
Implications
Certification: Provides mechanistic link between dietary Cr(VI) exposure and gut dysbiosis; relevant to understanding Cr-VI health effects at dietary exposure levels. Supports the case for distinguishing Cr-VI from total Cr in certification contexts. Courses: Useful illustration of gut microbiome disruption by hexavalent chromium via food-chain exposure. App: No direct contamination_profile data; supports metadata on Cr health mechanisms. Microbiome: Core reference for Cr(VI)-gut microbiome axis. Candidate for chromium-gut-axis page. Complements Chromium, Hexavalent.
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Update history
The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.
| Commit | Date | Change | Description |
|---|---|---|---|
| a8052bb | 2026-08-09 | major | 6 sections added; narrative text revised |