Research advances in the intestinal microbes in wild birds with different feeding habits

肠道微生物是庞大而多样的微生物群落，通过促进营养摄取、宿主防御、免疫调节等，在维持机体健康方面起着至关重要的作用。宿主外部或内部环境的任何变化都会影响肠道微生物的组成，鸟类具有复杂的生活史和多样化的食性，飞翔生活使它们的生理活动面临更大的选择性压力，导致肠道微生物菌群的变化更加复杂。近年来，随着基因测序技术的发展以及对鸟类肠道微生物研究的日益重视，导致了鸟类肠道微生物研究呈指数增长。但目前的研究主要以家禽为主，野生鸟类肠道微生物报道则相对较少。野生鸟类肠道微生物结构变化及其维持机制等的研究仍处于起步阶段，有较大的研究空间。从植食性、肉食性、杂食性三种食性的鸟类肠道微生物组成及特点、影响因素等方面对前人的文献进行了全面梳理，以期为野生鸟类肠道微生物研究提供参考。总的来说，植食性鸟类肠道微生物多样性最低，以高丰度的变形菌门（Proteobacteria）、厚壁菌门（Firmicutes）为主；而杂食性鸟类肠道微生物多样性最高。遗传、生活史特征、人类活动、城市化、圈养行为等对鸟类肠道微生物的组成具有显著性的影响。;The intestinal microbes are huge and diverse microbial communities, which play key roles in maintaining organism health through promoting nutrient uptake, defense, and immune regulation. However, any change in the intrinsic and extrinsic factors can affect the composition of gut microbiota, especially the food composition. The feeding habits of birds vary wildly, from fruit, seeds, foliage to carrion and capturing live animals. Bird life-history traits are diverse, such as migratory behavior, flight capacity, diet, mating systems, longevity and physiology, all of which may affect gut microbes. With the development of gene sequencing technology, and the increasing attention to intestinal microbes, intestinal bacterial diversity of birds has received some attention. However, publications are dominated by the studies of domestic poultry. The structure changes and maintenance mechanism, and the influencing factors of gut microbes in wild birds remain less studied. Here, we review current knowledge of the intestinal microbes in wild birds, to better understand the dynamics of wild bird gut microbiota, and will contribute to the future study of avian microbiology. In general, among the wild birds with different feeding habits, herbivorous birds have the lowest intestinal bacterial diversity, with high abundance of Proteobacteria and Firmicutes; and omnivorous birds have the highest intestines bacterial diversity. Genetics, life-history, human activities, urbanization, captive behaviors, etc. have significant effects on the bacterial diversity of wilds bird gut microbes.