Melville Dominik W, Meyer Magdalena, Kümmerle Corbinian, Alvarado-Barrantes Kevin A, Wilhelm Kerstin, Sommer Simone, Tschapka Marco, Risely Alice
Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, 89081 Ulm, Germany.
Escuela de Biología, Universidad de Costa Rica, 2060 San Jose, Costa Rica.
FEMS Microbiol Ecol. 2025 Jan 28;101(2). doi: 10.1093/femsec/fiaf012.
Diurnal rhythms of the gut microbiota are emerging as an important yet often overlooked facet of microbial ecology. Feeding is thought to stimulate gut microbial rhythmicity, but this has not been explicitly tested. Moreover, the role of the gut environment is entirely unexplored, with rhythmic changes to gut pH rather than feeding per se possibly affecting gut microbial fluctuations. In this study, we experimentally manipulated the feeding schedule of captive lesser long-nosed bats, Leptonycteris yerbabuenae, to dissociate photic and feeding cues, and measured the faecal microbiota and gut pH every 2 h. We detected strong diurnal rhythms in both microbial alpha diversity and beta diversity as well as in pH within the control group. However, a delay in feeding disrupted oscillations of gut microbial diversity and composition, but did not affect rhythms in gut pH. The oscillations of some genera, such as Streptococcus, which aid in metabolizing nutrients, shifted in accordance with the delayed-feeding cue and were correlated with pH. For other bacterial genera, oscillations were disturbed and no connection to pH was found. Our findings suggest that the rhythmic proliferation of bacteria matches peak feeding times, providing evidence that diurnal rhythms of the gut microbiota likely evolved to optimize their metabolic support to the host's circadian phenotype.
肠道微生物群的昼夜节律正成为微生物生态学中一个重要但常被忽视的方面。进食被认为会刺激肠道微生物的节律性，但这一点尚未得到明确验证。此外，肠道环境的作用完全未被探究，肠道pH值的节律性变化而非进食本身可能会影响肠道微生物的波动。在本研究中，我们通过实验操纵圈养的小长鼻蝠（Leptonycteris yerbabuenae）的进食时间表，以分离光照和进食线索，并每2小时测量一次粪便微生物群和肠道pH值。我们在对照组中检测到微生物α多样性和β多样性以及pH值都有强烈的昼夜节律。然而，进食延迟扰乱了肠道微生物多样性和组成的振荡，但并未影响肠道pH值的节律。一些有助于代谢营养物质的属，如链球菌，其振荡根据延迟进食线索发生了变化，并且与pH值相关。对于其他细菌属，振荡受到干扰，且未发现与pH值的关联。我们的研究结果表明，细菌的节律性增殖与进食高峰时间相匹配，这为肠道微生物群的昼夜节律可能是为了优化其对宿主昼夜表型的代谢支持而进化提供了证据。
