Abstract

Bottlenose dolphins (Tursiops truncatus), like other mammalian species, can experience intestinal dysbiosis, diarrhea, and other gastrointestinal illnesses. About 80% of the mammalian immune system resides in the intestines, therefore, gastrointestinal dysbiosis can cause enormous and broad-reaching impacts on the rest of the body.^1–3 Fecal microbiota transplantation (FMT) holds promise in dolphin medicine as a therapeutic tool to restore the microbiota and intestinal bile acid metabolism without antibiotic use.^2,4,5 Data regarding the use of FMT in dolphins to treat dysbiosis is, however, limited to few anecdotal reports.⁶ The goals of this prospective clinical study were to develop a health screening protocol for FMT donors, to develop an effective FMT administration protocol for use in managed dolphins, and to examine the efficacy of FMT therapy in three dolphins with dysbiosis utilizing metagenomic sequencing. Thirteen dolphins at the U.S. Navy Marine Mammal Program were included: 7 healthy fecal donors, 3 FMT recipients, and 3 controls. Comprehensive health monitoring was performed throughout the study on all dolphins. Fecal samples were collected before, during, and after FMT therapy, over a period of 20 months. Screening of donor and recipient fecal samples was accomplished by multiple reference lab diagnostics. Additionally, shotgun metagenomic sequencing was performed on all fecal samples. Baseline recipient fecal samples had significantly different beta and alpha diversity compared to the donor fecal microbiome. Following FMT therapy, the recipient microbiome was significantly altered compared to baseline. No adverse effects were observed following FMT therapy.

Acknowledgements

The authors thank the records office, animal care trainers, and veterinary staff at the U.S. Navy Marine Mammal Program and the National Marine Mammal Foundation for their excellent care of the Navy’s marine mammals and assistance with this project -especially Celeste Parry, Brittany Novick, Jammy Eichman, Anthony Perron, Leah Crafton, Noelle Verni, Courtney Luni, Hannah Bateman, Danielle Ram, Teri Wu, Keatyn Bucknam, Kimberly LeRoy, Carrie Espinosa, Dave Woods, and Megan Sereyko-Dunn.

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