Table 1_Comparative assessment of Texas horned lizard (Phrynosoma cornutum) gut microbiome diversity and composition throughout transition from captivity to wild.xlsx

Microbiomes play a key role in the health of animal hosts. To improve conservation translocation programs like headstarting, it is necessary to consider how the structure of these programs impact the host-associated microbiome. Bringing animals into captivity introduces novel diets and environments; however, the extent to which these factors contribute to the structure of the host’s gut microbiome remains poorly understood. Additionally, it is unclear if periods of captivity leave a lasting signature on the host-associated gut microbiome, which could impact individual health and fitness in the long-term. In this study, we repeatedly sampled the gut microbiome of a cohort of headstart Texas horned lizards (Phrynosoma cornutum) throughout their transition from captivity to the wild. We also collected samples of extrinsic microbial communities present in their captive and wild diet and environment. Finally, we sampled the gut microbiome of wild resident lizards to serve as a baseline comparison. Using 16S rRNA microbial inventories, we examined differences in microbial community composition and diversity between pre-release headstart, post-release headstart, and resident lizards of the wild population. Additionally, we assessed the contribution of environmental and dietary microbial communities to the assembly of P. cornutum gut microbiomes in captivity and the wild. Our results suggest captive P. cornutum harbor gut microbiomes that are distinct from their wild counterparts. However, within two-months post-release, the headstart gut microbiome restructures to be indistinguishable from the wild resident microbiome. Microbiomes associated with the captive diet and environment are distinct in beta diversity, but not alpha diversity, from those in the wild. Our results provide important insights into host-associated microbiome dynamics associated with transition from captivity to the wild and can be used to inform conservation translocation practices.

微生物组（microbiome）在动物宿主的健康中发挥关键作用。为优化诸如人工育幼放归（headstarting）这类保育易位项目，有必要厘清项目实施方式对宿主相关微生物组的影响。将动物圈养会引入全新的日粮与环境；然而，这些因素对宿主肠道微生物组结构的影响程度仍未得到充分阐明。此外，圈养阶段是否会在宿主相关肠道微生物组中留下持久印记，并长期影响个体健康与生存适合度，目前尚不明确。
本研究中，我们对一组经人工育幼放归的德克萨斯角蜥（Phrynosoma cornutum）从圈养到野外的过渡过程进行了肠道微生物组的重复采样。我们还采集了它们圈养日粮、野生日粮以及栖息环境中的外源微生物群落样本。最后，我们采集了野生定居蜥蜴的肠道微生物组样本，作为基线对照。
本研究基于16S rRNA微生物组测序数据，对比分析了放归前人工育幼个体、放归后人工育幼个体以及野生种群定居蜥蜴的微生物群落组成与多样性差异。此外，我们还评估了环境与日粮微生物群落在圈养及野生状态下对德克萨斯角蜥肠道微生物组组装的贡献。
研究结果显示，圈养德克萨斯角蜥的肠道微生物组与野生个体存在显著差异。
但在放归后的两个月内，人工育幼个体的肠道微生物组会发生重构，其组成与野生定居蜥蜴的微生物组已无显著差异。
圈养日粮与环境相关的微生物组在β多样性上与野生环境中的对应群落存在差异，但α多样性并无显著不同。
本研究结果为揭示圈养转归野外过程中的宿主相关微生物组动态提供了重要见解，可为保育易位实践提供科学参考。