An extensive network of microbial-host interactions exists in the gut, making the gut microbiome a complex ecosystem to untangle. The microbial composition and the fecal metabolites are important readouts to investigate intricate microbiota-diet-host interplay. However, this ecosystem is dynamic, and it is of interest to understand the degree and timescale of changes occurring in the gut microbiota, during disease as well as in healthy individuals. Cross-sectional study design is often used to investigate the microbiome, but this design provides a static snapshot and cannot provide evidence on the dynamic nature of the gut microbiome. Longitudinal studies are better suited to extrapolate causation in a study or assess changes over time. This study investigates longitudinal change in the gut microbiome and fecal metabolites in 14 healthy individuals with weekly sampling over a period of one-month (four time points), to elucidate the temporal changes occurring in the gut microbiome composition and fecal metabolites. Utilizing 16S rRNA amplicon sequencing for microbiome analysis and NMR spectroscopy for fecal metabolite characterization, we assessed the stability of these two types of measurable parameters in fecal samples during the period of one month. Our results show that the gut microbiome display large variations between healthy individuals, but relatively lower within-individual variations, which makes it possible to uniquely identify individuals. The fecal metabolites showed higher stability over time compared to the microbiome and exhibited consistently smaller variations both within and between individuals. This relative higher stability of the fecal metabolites suggests a balanced, consistent output even amid individual's differences in microbial composition and they can provide a viable complementary readout to better understand the microbiome activity.

中文翻译：

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在不同的肠道微生物组组成中粪便代谢物的稳定性：对健康个体变异性的为期一个月的纵向研究。


肠道中存在广泛的微生物-宿主相互作用网络，使肠道微生物组成为一个需要解开的复杂生态系统。微生物组成和粪便代谢物是研究复杂的微生物群-饮食-宿主相互作用的重要读数。然而，这个生态系统是动态的，了解肠道微生物群、疾病期间以及健康个体发生的变化的程度和时间尺度是很有趣的。横断面研究设计通常用于研究微生物组，但这种设计提供了静态快照，无法提供有关肠道微生物组动态性质的证据。纵向研究更适合于推断研究中的因果关系或评估随时间的变化。本研究调查了 14 名健康个体肠道微生物组和粪便代谢物的纵向变化，并在一个月的 （四个时间点） 内每周采样，以阐明肠道微生物组组成和粪便代谢物发生的时间变化。利用 16S rRNA 扩增子测序进行微生物组分析，利用 NMR 波谱进行粪便代谢物表征，我们评估了这两种类型的可测量参数在一个月内粪便样本中的稳定性。我们的结果表明，肠道微生物组在健康个体之间表现出较大的差异，但个体内的差异相对较低，这使得唯一识别个体成为可能。与微生物组相比，粪便代谢物随着时间的推移表现出更高的稳定性，并且在个体内和个体内都表现出始终较小的变化。 粪便代谢物的这种相对较高的稳定性表明，即使在个体微生物组成的差异下，也能产生平衡、一致的输出，并且它们可以提供可行的互补读数，以更好地了解微生物组活性。