title: Ontogenetic Differences in Dietary Fat Influence Microbiota Assembly in the Zebrafish Gut.
abstract: Gut microbiota influence the development and physiology of their animal hosts, and these effects are determined in part by the composition of these microbial communities. Gut microbiota composition can be affected by introduction of microbes from the environment, changes in the gut habitat during development, and acute dietary alterations. However, little is known about the relationship between gut and environmental microbiotas or about how host development and dietary differences during development impact the assembly of gut microbiota. We sought to explore these relationships using zebrafish, an ideal model because they are constantly immersed in a defined environment and can be fed the same diet for their entire lives. We conducted a cross-sectional study in zebrafish raised on a high-fat, control, or low-fat diet and used bacterial 16S rRNA gene sequencing to survey microbial communities in the gut and external environment at different developmental ages. Gut and environmental microbiota compositions rapidly diverged following the initiation of feeding and became increasingly different as zebrafish grew under conditions of a constant diet. Different dietary fat levels were associated with distinct gut microbiota compositions at different ages. In addition to alterations in individual bacterial taxa, we identified putative assemblages of bacterial lineages that covaried in abundance as a function of age, diet, and location. These results reveal dynamic relationships between dietary fat levels and the microbial communities residing in the intestine and the surrounding environment during ontogenesis.
  
  
  OBJECTIVE
  The ability of gut microbiota to influence host health is determined in part by their composition. However, little is known about the relationship between gut and environmental microbiotas or about how ontogenetic differences in dietary fat impact gut microbiota composition. We addressed these gaps in knowledge using zebrafish, an ideal model organism because their environment can be thoroughly sampled and they can be fed the same diet for their entire lives. We found that microbial communities in the gut changed as zebrafish aged under conditions of a constant diet and became increasingly different from microbial communities in their surrounding environment. Further, we observed that the amount of fat in the diet had distinct age-specific effects on gut community assembly. These results reveal the complex relationships between microbial communities residing in the intestine and those in the surrounding environment and show that these relationships are shaped by dietary fat throughout the life of animal hosts.
authors.affiliation: Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, USA Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Sandi
authors.initials: S
authors.lastname: Wong
authors.affiliation: Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA.
authors.forename: W Zac
authors.identifier: http://orcid.org/0000-0002-8072-9023
authors.initials: WZ
authors.lastname: Stephens
authors.affiliation: Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon, USA.
authors.forename: Adam R
authors.initials: AR
authors.lastname: Burns
authors.affiliation: Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon, USA.
authors.forename: Keaton
authors.initials: K
authors.lastname: Stagaman
authors.affiliation: Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, USA.
authors.forename: Lawrence A
authors.initials: LA
authors.lastname: David
authors.affiliation: Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon, USA.
authors.forename: Brendan J M
authors.initials: BJ
authors.lastname: Bohannan
authors.affiliation: Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Guillemin
authors.affiliation: Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, USA Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA john.rawls@duke.edu.
authors.forename: John F
authors.initials: JF
authors.lastname: Rawls
mesh_terms: D000818:Animals; D016000:Cluster Analysis; D003430:Cross-Sectional Studies; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D004041:Dietary Fats; D000069196:Gastrointestinal Microbiome / Q000187:drug effects*; D041981:Gastrointestinal Tract / Q000382:microbiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D015027:Zebrafish / Q000382:microbiology*
chemical_list: D004275:DNA, Ribosomal; D004041:Dietary Fats; D012336:RNA, Ribosomal, 16S