Abstract
Green turtle is an endangered marine herbivore that breaks down food particles, primarily sea grasses, through microbial fermentation.1,2,3 However, the microbial community and its role in health and disease are still largely unexplored. In this study, we investigated and compared the fecal bacterial communities of wild-captured green turtles to stranded turtles by PCR amplification of a hypervariable region (V1-V3) of the bacterial 16S rRNA gene. A total of 12 samples were sequenced using next generation high-throughput sequencing technology on an Illumina MiSeq platform.3 At a phylum level, Firmicutes predominated among wild-captured green turtles, followed by Bacteroidetes and Proteobacteria. In contrast, Proteobacteria (Gammaproteobacteria) was the most significantly dominant phylum among all stranded turtles, followed by Bacteroidetes and Firmicutes. In addition, Fusobacteria was also significantly abundant in stranded turtles. No significant differences were found between the wild-captured turtles from two different locations. At a family level, 25 of the 53 families were identified in both the wild-captured and stranded green turtles, while 14 families were found only in stranded turtles. At the OTU level, 256 (48.7%) of the total OTUs (>1% abundance) were shared between the wild-captured groups of turtles, while absent in stranded turtles. The predominance of Bacteroides in all groups indicates the importance of this bacteria in turtle gut health. In terms of microbial diversity and richness, wild-captured green turtles showed the highest microbial diversity and richness compared to stranded turtles. The marked differences in the bacterial communities between wild-captured and stranded turtles suggest the possible dysbiosis in stranded turtles in addition to potential causal agents.
Acknowledgements
The authors would like to thank all volunteers for their contributions during samples collection. We specially thank Stephen Menzies and Krystal Huff from ReefHQ Turtle Hospital, Townsville, QLD for their cooperation during sample collection. We thank Gudjuda and Girringun community people for their support during field sampling. We thank Dr. Leigh Owens and Dr. Jacqueline Picard from James Cook University, QLD for useful advice on sample processing and statistical analysis.
* Presenting author
+ Student presenter
Literature Cited
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3. IUCN. 2000. 2000 IUCN red list of threatened species. The IUCN Species Survival Commission. - www.iucnredlist.org.
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