Knowledge is growing on how gut microbiota are established, but the effects of maternal symbiotic microbes throughout early microbial successions in birds remain elusive. In this study, we examined the contributions and transmission modes of maternal microbes into the neonatal microbiota of a passerine, the zebra finch (Taeniopygia guttata), based on fostering experiments. Using 16S rRNA amplicon sequencing, we found that zebra finch chicks raised by their biological or foster parents (the society finch Lonchura striata domestica) had gut microbial communities converging with those of the parents that reared them. Moreover, source-tracking models revealed high contribution of zebra finches’ oral cavity/crop microbiota to their chicks’ early gut microbiota, which were largely replaced by the parental gut microbiota at later stages. The results suggest that oral feeding only affects the early stage of hatchling gut microbial development. Our study indicates that passerine chicks mainly acquire symbionts through indirect maternal transmission—passive environmental uptake from nests that were smeared with the intestinal and cloacal microbes of parents that raised them. Gut microbial diversity was low in hand-reared chicks, emphasizing the importance of parental care in shaping the gut microbiota. In addition, several probiotics were found in chicks fostered by society finches, which are excellent foster parents for other finches in bird farms and hosts of brood parasitism by zebra finches in aviaries; this finding implies that avian species that can transfer probiotics to chicks may become selectively preferred hosts of brood parasitism in nature.

中文翻译：

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母体肠道微生物通过巢穴塑造雀形目雏鸟肠道微生物群的早期组装。


关于肠道微生物群如何建立的知识正在不断增长，但母体共生微生物在鸟类早期微生物演替过程中的影响仍然难以捉摸。在这项研究中，我们基于培育实验，研究了母体微生物对雀形目斑胸草雀（Taeniopygia guttata）新生儿微生物群的贡献和传播模式。使用 16S rRNA 扩增子测序，我们发现由亲本或养父母（社会雀 Lonchura striata Domestica）抚养的斑胸草雀雏鸟的肠道微生物群落与养育它们的父母的肠道微生物群落一致。此外，源追踪模型显示斑胸草雀的口腔/作物微生物群对其雏鸟早期肠道微生物群的贡献很大，而这些微生物群在后期大部分被亲代肠道微生物群所取代。结果表明，口服喂养仅影响孵化期肠道微生物发育的早期阶段。我们的研究表明，雀形目雏鸟主要通过间接母体传播获得共生体，即从涂有养育它们的父母的肠道和泄殖腔微生物的巢穴中被动吸收环境。手工饲养的雏鸡肠道微生物多样性较低，这强调了父母的照顾在塑造肠道微生物群方面的重要性。此外，在群居雀所养育的雏鸟中也发现了多种益生菌，这些雏鸟是养禽场中其他雀类的优秀养父母，也是鸟舍中斑胸草雀的巢寄生宿主；这一发现意味着，能够将益生菌转移给雏鸡的鸟类物种可能成为自然界中巢寄生的选择性首选宿主。