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.