DOI: 10.5061/dryad.42f2q
title: Data from: Diet and phylogeny shape the gut microbiota of Antarctic seals: a comparison of wild and captive animals

description: The gut microbiota of mammals underpins the metabolic capacity and health
 of the host. Our understanding of what influences the composition of this
 community has been limited primarily to evidence from captive and
 terrestrial mammals. Therefore, the gut microbiota of southern elephant
 seals, Mirounga leonina, and leopard seals, Hydrurga leptonyx, inhabiting
 Antarctica were compared with captive leopard seals. Each seal exhibited a
 gut microbiota dominated by four phyla: Firmicutes (41.5 ± 4.0%),
 Fusobacteria (25.6 ± 3.9%), Proteobacteria (17.0 ± 3.2%) and Bacteroidetes
 (14.1 ± 1.7%). Species, age, sex and captivity were strong drivers of the
 composition of the gut microbiota, which can be attributed to differences
 in diet, gut length and physiology and social interactions. Differences in
 particular prey items consumed by seal species could contribute to the
 observed differences in the gut microbiota. The longer gut of the southern
 elephant seal provides a habitat reduced in available oxygen and more
 suitable to members of the phyla Bacteroidetes compared with other hosts.
 Among wild seals, 16 ‘core’ bacterial community members were present in
 the gut of at least 50% of individuals. As identified between southern
 elephant seal mother–pup pairs, ‘core’ members are passed on via vertical
 transmission from a young age and persist through to adulthood. Our study
 suggests that these hosts have co-evolved with their gut microbiota and
 core members may provide some benefit to the host, such as developing the
 immune system. Further evidence of their strong evolutionary history is
 provided with the presence of 18 shared ‘core’ members in the gut
 microbiota of related seals living in the Arctic. The influence of diet
 and other factors, particularly in captivity, influences the composition
 of the community considerably. This study suggests that the gut microbiota
 has co-evolved with wild mammals as is evident in the shared presence of
 ‘core’ members.
description: Diet & phylogeny
 shape Antarctic seal gut microbiotaFaecal samples were
 collected from southern elephant seals (n=24) and leopard seals (n=12) in
 the western Antarctic using rectal swabs. Sterile swabs (Oxoid Australia
 Pty, SA, Australia)were used and samples were frozen after collection.
 Faecal samples were collected opportunistically after defecation from
 captive leopard seals (n=2) housed at Taronga Zoo, Sydney, NSW, Australia.
 Total genomic DNA was extracted using QIAamp Stool DNA Mini Kit (Qiagen
 Pty, Vic., Australia) following the manufacturers protocol. Pyrosequencing
 of the16S rRNA gene was carried out at the Research and Testing Laboratory
 (Lubbock, TX, USA). Primers 27F 5′-AGAGTTTGATCCTGGCTCAG-3′ and 519R
 5′-GTATTACCGCGGCTGCTG-3′ were used (Lane et al., 1985, PNAS USA,
 82(20):6955-6959). PCR reactions were carried out individually for each
 sample using ~ 10 ng of template DNA. Tagged primer pairs and PCR reaction
 conditions followed the protocol of Dowd et al., 2008 (Foodborne Pathogens
 & Disease, 5(4):459-472). Sequencing was carried out on a Roche 454
 titanium sequencer. Sequence data were trimmed to between 200 and 600 bp
 and labelled using the Mothur v.1.13.0 suite of programs (Schloss et al.,
 2009, Applied & Environmental Microbiology,
 75(23):7357-7541).