Fecal microbiota characterization Seychelles giant tortoises (Aldabrachelys gigantea) living in in wild and in controlled environment.
All animals are colonized by a microbiome, defined as a complex collection of microorganisms and their genetic material. Studies on gut microbiomes of different animals have provided many ecological and evolutionary information showing a strict link with health and disease conditions. Therefore few researches concern reptile gut microbiota, mainly on carnivorous ones, have been performed. Moreover, there are very few studies that compare gut microbiota of animals housed in controlled conditions or in wild habitat. The aim of this study is to characterize the fecal microbial community of Aldabrachelys gigantea, herbivorous giant tortoises, living in different environmental conditions, on the Seychelles Islands and in Italy. Seventeen individual fecal samples collected from giant tortoises located in Curieuse Island (CI), in Botanical Garden (BG) at Mahé, both are Seychelles Islands and at Parco Natura Viva – Garda Zoological Park (PNV) in Verona, in Italy have been studied. Samples have been analyzed for the V3-V4 regions of the 16S rRNA gene to characterize the gut microbiota profile. A total of 25 Phyla (42 % Bacteroidetes, 32% Firmicutes), 167 Families (14% Ruminococcaceae, 14% Rikenellaceae) and 310 Genera (7% Treponema, 6% Rikenellaceae_RC9_gut_group) were identified. A higher microbial diversity (alpha indices) was observed for the BG samples compared to the PNV samples (Shannon: 5.39 vs 4.43; InvSimpson: 80.7 vs 25; Chao1: 584 vs 377 p = 0.05). Moreover, our results show a significant difference of beta diversity between samples from CI, BG and PNV (p =0.001) suggesting a different bacterial composition of the stool samples of giant tortoises at the different locations. This study has helped to provide novel insights into the effects of different environmental conditions on the microbial communities of the gut microbiota of the giant tortoises. In particular important and valuable information about differences between natural and controlled environment on bacterial gut community structure could drive to help in better managing of giant tortoises in a controlled environment.