The effect of diet on the gastrointestinal microbiome of juvenile rehabilitating green turtles (Chelonia mydas)

• Published in: PloS one Vol. 15; no. 1; p. e0227060
• Main Authors: Bloodgood, Jennifer C G, Hernandez, Sonia M, Isaiah, Anitha, Suchodolski, Jan S, Hoopes, Lisa A, Thompson, Patrick M, Waltzek, Thomas B, Norton, Terry M
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01-01-2020; Public Library of Science (PLoS)
• Subjects: Algae; Animal protein; Animals; Antibiotics; Apalone ferox; Appetite loss; Aquatic reptiles; Bacteria - classification; Bacteria - isolation & purification; Bacteroidetes; Biology and Life Sciences; Caretta caretta; Chelonia mydas; Community composition; Diet; Ecology and Environmental Sciences; Endangered Species; Environmental protection; Fecal microflora; Feces; Feces - microbiology; Firmicutes; Food sources; Gastrointestinal Microbiome; Immunology; Infectious diseases; Influence; Juveniles; Laboratories; Medicine and Health Sciences; Microbiomes; Microbiota; Natural resources; Next-generation sequencing; Pelodiscus sinensis; Polysaccharides; Proteins; Recovery; Rehabilitation; Saccharides; Saline water; Sea turtles; Seafood; Turtles - microbiology; Vegetables; Veterinary colleges; Veterinary medicine; Georgia; Florida; United States > US; Texas; Jekyll Island Georgia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0227060

Threatened and endangered green turtles (Chelonia mydas) are unique because as juveniles they recruit from pelagic to near-shore waters and shift from an omnivorous to primarily herbivorous diet (i.e. seagrass and algae). Nevertheless, when injured and ill animals are admitted to rehabilitation, animal protein (e.g. seafood) is often offered to combat poor appetite and emaciation. We examined how the fecal microbiome of juvenile green turtles changed in response to a dietary shift during rehabilitation. We collected fecal samples from January 2014 -January 2016 from turtles (N = 17) in rehabilitation at the Georgia Sea Turtle Center and used next generation sequencing to analyze bacterial community composition. Samples were collected at admission, mid-rehabilitation, and recovery, which entailed a shift from a mixed seafood-vegetable diet at admission to a primarily herbivorous diet at recovery. The dominant phyla changed over time, from primarily Firmicutes (55.0%) with less Bacteroidetes (11.4%) at admission, to primarily Bacteroidetes (38.4%) and less Firmicutes (31.8%) at recovery. While the microbiome likely shifts with the changing health status of individuals, this consistent inversion of Bacteroidetes and Firmicutes among individuals likely reflects the increased need for protein digestion, for which Bacteroidetes are important. Firmicutes are significant in metabolizing plant polysaccharides; thus, fewer Firmicutes may result in underutilization of wild diet items in released individuals. This study demonstrates the importance of transitioning rehabilitating green turtles to an herbivorous diet as soon as possible to afford them the best probability of survival.