Gut microbiota response of tuatara (Sphenodon punctatus) to dietary manipulation and captivity

The microbiota of a hosts digestive tract play crucial roles in digestion and pathogen resistance. Hosts captive in zoos often have more human interaction and antibiotic use, in addition to differences in diet and environment, compared to their wild counterparts. Consequently, wild and captive animals frequently harbour different microbial communities. We tested whether diversity of diet provided in captivity shifts the gut microbiota of tuatara, an endemic reptile to New Zealand, at three captive sites, and how the gut community of these tuatara compares to those in the wild. Dietary manipulation did not cause a strong overall shift in the tuatara gut microbiota, but individual tuatara did experience microbial shifts during manipulation, which subsequently reverted after manipulation. We found that Bacteroides, a genus common in most vertebrate guts but rare in tuatara, increased significantly in the gut during manipulation, then decreased post-manipulation. Finally, the gut microbiotas of captive tuatara significantly differed from those of wild tuatara, though most of the dominant bacterial genera found in wild tuatara persisted in captive tuatara. This work represents a first look at the captive tuatara gut microbiota, and establishes how sensitive the gut community is to dietary manipulation and captivity for this relict reptile.

宿主消化道的微生物群在消化过程与病原体抵御中发挥关键作用。与野生同类相比，圈养于动物园的宿主往往会接触更多人类、使用更多抗生素，同时饮食与环境也存在差异。因此，野生动物与圈养动物的肠道定植着不同的微生物群落。本研究在三个圈养位点开展实验，探究圈养环境中提供的多样化饮食是否会改变新西兰特有孑遗爬行动物喙头蜥（tuatara）的肠道微生物群，并对比这些圈养喙头蜥与野生喙头蜥的肠道群落差异。饮食干预并未使喙头蜥的肠道微生物群发生显著的整体变化，但个体喙头蜥在干预期间确实出现了微生物群落的改变，且该改变在干预结束后可恢复至初始状态。研究发现，拟杆菌属（Bacteroides）——一类在多数脊椎动物肠道中常见但在喙头蜥肠道中较为罕见的菌属——在干预期间于喙头蜥肠道内的丰度显著上升，干预结束后则出现下降。最终结果显示，圈养喙头蜥的肠道微生物群与野生喙头蜥存在显著差异，尽管野生喙头蜥肠道内的多数优势细菌菌属在圈养个体中仍得以保留。本研究是首次对圈养喙头蜥肠道微生物群的探究，明确了这种孑遗爬行动物的肠道群落对饮食干预与圈养环境的敏感程度。