Related Experiment Video
Updated: Sep 9, 2025
Quantitative Polymerase Chain Reaction-based Analyses of Murine Intestinal Microbiota After Oral Antibiotic Treatment
Published on: November 17, 2018
Dietary Iron Intake Impacts the Microbial Composition of the Murine Intestinal and Lung Microbiome
Ama-Tawiah Essilfie1,2, Alison Smith1, Rebecca Watts1
1QIMR Berghofer Medical Research Institute, Brisbane, QLD 4006, Australia.
Background:
Iron is an essential nutrient for many bacterial pathogens and normal cellular function and homeostasis of their hosts. Studies suggest that iron deficiency or overload may contribute to the pathogenesis of several chronic conditions and modify host-microbial interactions. In this study, we assessed the impact of varying dietary iron intakes on the microbiota of the intestinal tract and lungs of wild-type mice.
Methods:
Male C57BL/6J mice were fed either a standard pellet chow (high iron diet), a ferrous ammonium sulfate (FeAS)-supplemented diet or an iron-deficient diet for four weeks. Tissue from the lung, duodenum and colon was collected, and 16S rRNA gene fragments were pyrosequenced.
Results:
Total serum iron levels were negatively associated with richness of the lung microbiome (p = 0.035). In the murine lungs, there was no association between the iron diet and the overall lung microbiota community composition, but Bacteroides spp. were significantly enriched in the lungs of mice fed the FeAS diet (LDA score > 4, p < 0.05). The community composition of the intestinal microbiota changed significantly depending on the iron diet, with increased richness in the low-iron compared to the iron-supplemented groups (p = 0.053). In the duodenum, Prevotella spp. were reduced (Mean = 7.869, SEM = 3.464, p < 0.05), and Desulfovibrio species increased (Mean = 5.343, SEM = 1.362, p < 0.001) in iron-supplemented groups compared to the low-iron-diet group. In the colon, Bifidobacterium and Bacteroides species were reduced (Mean = 7.175, SEM = 2.246, p < 0.01 and Mean = 6.967, SEM = 1.834, p < 0.01 respectively), and Pseudomonas increased (Mean = 24.03, SEM = 8.919, p < 0.05) in mice on higher-iron diets compared to the low-iron diet.
Discussion:
This study demonstrates that dietary iron intake significantly impacts the intestinal microbiota and has a small, yet significant, effect on the lung microbiome in C57BL/6J mice. Whilst dietary iron content per se did not significantly modulate the composition of the lung microbiota, serum iron levels had subtle impacts on the community composition of the lung microbiota.
Insights
Dietary iron intake significantly alters gut microbiota composition and richness in mice. While lung microbiota were less affected, high iron diets impacted specific bacterial populations in both the intestines and lungs.
Area of Science:
- Microbiology
- Nutritional Science
- Host-Microbe Interactions
Background:
- Iron is crucial for bacterial pathogens and host homeostasis.
- Dietary iron levels (deficiency or overload) may influence chronic diseases and host-microbial dynamics.
- Understanding iron's impact on microbiota is vital for host health.
Purpose of the Study:
- To investigate the effects of varying dietary iron intakes on the intestinal and lung microbiota of mice.
- To determine how iron influences microbial community composition and richness in different body sites.
Main Methods:
- Male C57BL/6J mice were assigned to high-iron (chow), iron-supplemented (FeAS), or iron-deficient diets for four weeks.
- 16S rRNA gene sequencing was performed on lung, duodenum, and colon tissue samples.
- Serum iron levels were measured and correlated with microbiome data.
Main Results:
- Serum iron negatively correlated with lung microbiome richness (p=0.035).
- Intestinal microbiota composition significantly shifted with diet, showing increased richness in low-iron groups.
- Specific bacterial changes included enrichment of *Bacteroides* in lungs (FeAS diet), reduction of *Prevotella* and increase of *Desulfovibrio* in the duodenum, and reduction of *Bifidobacterium*/*Bacteroides* with increased *Pseudomonas* in the colon under higher-iron conditions.
Conclusions:
- Dietary iron significantly modulates the intestinal microbiota in mice.
- A subtle but significant impact of dietary iron on the lung microbiome was observed.
- Serum iron levels showed a modest influence on lung microbial community structure.
