Mu et al. 2023 — Seaweed polysaccharide ameliorates Cr(VI)-induced gut microbiome dysbiosis in mice
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.