Liukkonen Martta, Hukkanen Mikaela, Cossin-Sevrin Nina, Stier Antoine, Vesterinen Eero, Grond Kirsten, Ruuskanen Suvi
Department of Biological and Environmental Science, University of Jyväskylä, Jyvaskyla, Finland.
Department of Biology, University of Turku, Turku, Finland.
Anim Microbiome. 2023 Mar 22;5(1):19. doi: 10.1186/s42523-023-00241-z.
The gut microbiome forms at an early stage, yet data on the environmental factors influencing the development of wild avian microbiomes is limited. As the gut microbiome is a vital part of organismal health, it is important to understand how it may connect to host performance. The early studies with wild gut microbiome have shown that the rearing environment may be of importance in gut microbiome formation, yet the results vary across taxa, and the effects of specific environmental factors have not been characterized. Here, wild great tit (Parus major) broods were manipulated to either reduce or enlarge the original brood soon after hatching. We investigated if brood size was associated with nestling bacterial gut microbiome, and whether gut microbiome diversity predicted survival. Fecal samples were collected at mid-nestling stage and sequenced with the 16S rRNA gene amplicon sequencing, and nestling growth and survival were measured.
Gut microbiome diversity showed high variation between individuals, but this variation was not significantly explained by brood size or body mass. Additionally, we did not find a significant effect of brood size on body mass or gut microbiome composition. We also demonstrated that early handling had no impact on nestling performance or gut microbiome. Furthermore, we found no significant association between gut microbiome diversity and short-term (survival to fledging) or mid-term (apparent juvenile) survival.
We found no clear association between early-life environment, offspring condition and gut microbiome. This suggests that brood size is not a significantly contributing factor to great tit nestling condition, and that other environmental and genetic factors may be more strongly linked to offspring condition and gut microbiome. Future studies should expand into other early-life environmental factors e.g., diet composition and quality, and parental influences.
肠道微生物群在早期阶段形成，但关于影响野生鸟类微生物群发育的环境因素的数据有限。由于肠道微生物群是机体健康的重要组成部分，了解其与宿主表现之间的联系很重要。早期对野生肠道微生物群的研究表明，饲养环境可能对肠道微生物群的形成很重要，但结果因分类群而异，且特定环境因素的影响尚未得到明确描述。在这里，对野生大山雀（Parus major）的雏鸟在孵化后不久进行处理，以减少或扩大原窝雏鸟数量。我们调查了窝雏数是否与雏鸟肠道细菌微生物群相关，以及肠道微生物群多样性是否能预测存活率。在雏鸟中期收集粪便样本，并用16S rRNA基因扩增子测序进行分析，并测量雏鸟的生长和存活情况。
肠道微生物群多样性在个体间表现出很大差异，但这种差异不能由窝雏数或体重显著解释。此外，我们没有发现窝雏数对体重或肠道微生物群组成有显著影响。我们还证明，早期处理对雏鸟表现或肠道微生物群没有影响。此外，我们没有发现肠道微生物群多样性与短期（存活至离巢）或中期（明显的幼年期）存活率之间存在显著关联。
我们没有发现早期生活环境、后代状况与肠道微生物群之间存在明显关联。这表明窝雏数不是影响大山雀雏鸟状况的显著因素，其他环境和遗传因素可能与后代状况和肠道微生物群的联系更为紧密。未来的研究应扩展到其他早期生活环境因素，如饮食组成和质量以及亲代影响。
