Fecal microbiota of captive Antillean manatee Trichechus manatus manatus

Herbivorous animals have unique intestinal microbiota that greatly helps with plant digestion in the host; however, knowledge on the microbiota of marine herbivores is limited. To better understand the taxonomy of intestinal microbiota in manatees, and the possible effects of captive conditions on that, we characterized the fecal microbiota of captive Antillean manatee Trichechus manatus manatus and compared the bacterial community with that of wild Florida manatees Trichechus manatus latirostris. Fecal samples were collected from four captive Antillean manatees in Ocean Expo Park, Okinawa, Japan. The high-quality sequences of the V3-V4 region of bacterial 16S rRNA obtained using an Illumina MiSeq platform were assigned to 16 bacterial phyla, and the most dominant was Firmicutes (84.05 ± 3.50%), followed by Bacteroidetes (8.60 ± 1.71%). Seven of the top 20 bacterial genera were responsible for hydrolyzing cellulose and metabolizing bile acid. The microbiota composition was remarkably different from that found in wild Florida manatees and more diverse than the composition in wild Florida manatees; hence, this result may be dependent on a captive environment. Our results highlight the unique intestinal microbiota in captive manatees, reflecting their diet and possibly an impact of the captive environment.