Bacterial Community in the Crop of the Hoatzin, a Neotropical Folivorous Flying Bird

ABSTRACTThe hoatzin is unique among known avian species because of the fermentative function of its enlarged crop. A small-bodied flying foregut fermenter is a paradox, and this bird provides an interesting model to examine how diet selection and the gut microbiota contribute to maximizing digestive efficiency. Therefore, we characterized the bacterial population in the crop of six adult hoatzins captured from the wild. A total of 1,235 16S rRNA gene sequences were grouped into 580 phylotypes (67% of the pooled species richness sampled, based on Good's coverage estimator, with CACEand Chao1 estimates of 1,709 and 1,795 species-level [99% identity] operational taxonomic units, respectively). Members of 9 of the ∼75 known phyla inBacteriawere identified in this gut habitat; theFirmicuteswere dominant (67% of sequences, belonging to the classesClostridia,Mollicutes, andBacilli), followed by theBacteroidetes(30%, mostly in the orderBacteroidales),Proteobacteria(1.8%), andLentisphaerae,Verrucomicrobia, TM7,Spirochaetes,Actinobacteria, andAminanaerobia(all <0.1%). The novelty in this ecosystem is great; 94% of the phylotypes were unclassified at the “species” level and thus likely include novel cellulolytic lineages.

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