Institute of Food, Nutrition and Health, Zurich, Switzerland.
J Nutr. 2012 Feb;142(2):271-7. doi: 10.3945/jn.111.148643. Epub 2011 Dec 21.
Iron (Fe) deficiency anemia is a global health concern and Fe fortification and supplementation are common corrective strategies. Fe is essential not only for the human host but also for nearly all gut bacteria. We studied the impact of Fe deficiency and Fe repletion on the gut microbiota in rats. Weanling rats were fed an Fe-deficient diet for 24 d and then repleted for 13 d with FeSO₄ (n = 15) or electrolytic Fe (n = 14) at 10 and 20 mg Fe · kg diet⁻¹. In addition, one group of rats (n = 8) received the Fe-deficient diet and one group (n = 3) received a Fe-sufficient control diet for all 37 d. Fecal samples were collected at baseline and after the depletion and repletion periods, and colonic tissues were examined histologically. Microbial metabolite composition in cecal water was measured and fecal samples were analyzed for microbial composition with temporal temperature gradient gel electrophoresis and qPCR. Compared to Fe-sufficient rats, Fe-deficient rats had significantly lower concentrations of cecal butyrate (-87%) and propionate (-72%) and the abundance of dominant species was strongly modified, including greater numbers of lactobacilli and Enterobacteriaceae and a large significant decrease of the Roseburia spp./E. rectale group, a major butyrate producer. Repletion with 20 mg FeSO₄ · kg diet⁻¹ significantly increased cecal butyrate concentrations and partially restored bacterial populations compared to Fe-deficient rats at endpoint. The effects on the gut microbiota were stronger in rats repleted with FeSO₄ than in rats repleted with electrolytic Fe, suggesting ferrous Fe may be more available for utilization by the gut microbiota than elemental Fe. Repletion with FeSO₄ significantly increased neutrophilic infiltration of the colonic mucosa compared to Fe-deficient rats. In conclusion, Fe depletion and repletion strongly affect the composition and metabolic activity of rat gut microbiota.
缺铁性贫血是一个全球性的健康问题，铁强化和补充是常见的纠正策略。铁不仅对人类宿主至关重要，对几乎所有肠道细菌也是必不可少的。我们研究了缺铁和补铁对大鼠肠道微生物群的影响。我们用缺铁饮食喂养断奶大鼠 24 天，然后用硫酸亚铁（n = 15）或电解铁（n = 14）分别以 10 和 20 mg Fe · kg 饮食⁻¹的剂量补充 13 天。此外，一组大鼠（n = 8）接受缺铁饮食，一组大鼠（n = 3）接受所有 37 天的铁充足对照饮食。在基线和耗竭和补充期后收集粪便样本，并检查结肠组织的组织学。测量盲肠水中微生物代谢产物的组成，并通过时间温度梯度凝胶电泳和 qPCR 分析粪便样本中的微生物组成。与铁充足的大鼠相比，缺铁的大鼠盲肠丁酸（-87%）和丙酸（-72%）浓度明显降低，优势种的丰度也发生了强烈的改变，包括乳杆菌和肠杆菌科的数量增加，以及主要的丁酸生产者罗斯伯里氏菌/直肠真杆菌组的数量显著减少。与缺铁大鼠相比，20 mg FeSO₄ · kg 饮食⁻¹补充可显著增加盲肠丁酸浓度，并在终点时部分恢复细菌种群。用硫酸亚铁补充的大鼠对肠道微生物群的影响比用电解铁补充的大鼠更强，这表明二价铁可能比元素铁更容易被肠道微生物群利用。与缺铁大鼠相比，用硫酸亚铁补充会显著增加结肠黏膜的中性粒细胞浸润。总之，缺铁和补铁强烈影响大鼠肠道微生物群的组成和代谢活性。
