Cloacal microbiota of barn swallows from Northern Italy

Bird gut microbiota shows large variation among geographical populations of the same species – probably because, differently from mammals, gut microbiota of birds is largely affected by extrinsic factors such as diet and environmental conditions. We analysed the cloacal microbiota (CM) of 12 barn swallows (Hirundo rustica) from a colony in Northern Italy by high-throughput DNA sequencing of the 16S rRNA gene. The CMs, dominated by bacteria of the phyla Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes, did not significantly differ between adult females, adult males and fledglings. This first description of barn swallow CM in Italy, together with two previous studies from Europe, suggests that CMs of geographically different barn swallow populations are dominated by bacteria belonging to the same phyla but different genera. The intra-colony similarity of the CMs may be due to the exposure of individuals to the same local environmental conditions while on their breeding grounds.

同种鸟类不同地理种群间的肠道菌群存在显著差异——这与哺乳动物的情况有所不同，鸟类的肠道菌群在很大程度上受饮食、环境条件等外在因素影响。本研究通过16S rRNA基因高通量DNA测序技术，对意大利北部一个种群的12只家燕（Hirundo rustica）的泄殖腔菌群（cloacal microbiota, CM）进行了分析。该种群的泄殖腔菌群以变形菌门（Proteobacteria）、放线菌门（Actinobacteria）、厚壁菌门（Firmicutes）和拟杆菌门（Bacteroidetes）的细菌为主，且在成年雌燕、成年雄燕与雏燕之间无显著差异。本次针对意大利家燕泄殖腔菌群的首次报道，结合欧洲此前的两项相关研究，表明不同地理种群的家燕泄殖腔菌群均以同一门类的细菌为主，但所属菌属存在差异。该种群内泄殖腔菌群的相似性，可能源于个体在繁殖栖息地上暴露于相同的局部环境条件之中。