Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
Department of Biology, University of Maryland, College Park, MD 20742, USA.
J Exp Biol. 2018 Oct 19;221(Pt 20):jeb187559. doi: 10.1242/jeb.187559.
Environmental temperature and gut microbial communities can both have profound impacts on the digestive performance of ectothermic vertebrates. Additionally, the diversity, composition and function of gut microbial communities themselves are influenced by temperature. It is typically assumed that the temperature-dependent nature of ectotherm digestive performance is due to factors such as host physiological changes and adaptation to local climatic conditions. However, it is also possible that temperature-induced alterations to gut microbiota may influence the relationship between temperature and digestion. To explore the connections between these three factors, we compared digestive performance and gut microbial community diversity and composition in red-backed salamanders housed at three experimental temperatures: 10, 15 and 20°C. We also investigated associations between specific bacterial taxa and temperature or salamander digestive performance. We found that salamander digestive performance was greatest at 15°C, while gut microbial diversity was reduced at 20°C. Further, gut microbial community composition differed among the three temperature treatments. The relative abundance of 25 bacterial genera was dependent on temperature, with high temperatures being associated with reductions in the relative abundance of disease-resistant bacteria and increases in pathogenic taxa. The relative abundance of four bacterial genera was correlated with salamander energy assimilation, two of which are known to digest chitin, a main component of the red-backed salamander diet. These findings suggest that gut microbiota may mediate the relationship between temperature and digestion in ectotherms. We discuss how global climate change may impact ectotherms by altering host-microbe interactions.
环境温度和肠道微生物群落都可以对变温脊椎动物的消化性能产生深远影响。此外，肠道微生物群落的多样性、组成和功能也受到温度的影响。通常认为，变温动物消化性能的温度依赖性是由于宿主生理变化和对当地气候条件的适应等因素造成的。然而，也有可能是温度诱导的肠道微生物群的改变会影响温度与消化之间的关系。为了探索这三个因素之间的联系，我们比较了在三个实验温度（10、15 和 20°C）下饲养的红背蝾螈的消化性能和肠道微生物群落多样性和组成。我们还调查了特定细菌类群与温度或蝾螈消化性能之间的关联。我们发现，蝾螈的消化性能在 15°C 时最佳，而在 20°C 时肠道微生物多样性降低。此外，肠道微生物群落组成在三种温度处理之间存在差异。25 个细菌属的相对丰度取决于温度，高温与疾病抗性细菌相对丰度的降低和致病性类群的增加有关。四个细菌属的相对丰度与蝾螈的能量同化有关，其中两个已知能够消化红背蝾螈饮食中的主要成分几丁质。这些发现表明，肠道微生物群可能在变温动物中调节温度与消化之间的关系。我们讨论了全球气候变化如何通过改变宿主-微生物相互作用来影响变温动物。
