Differences in crop bacterial community structure between hoatzins from different geographical locations.

The hoatzin is the only known folivorous bird with foregut fermentation, and is distributed in Venezuela in rivers of the central savannas to the eastern Orinoco River. Differences in diet are expected to affect the digestive microbiota and we hypothesized that hoatzins from different habitats might have a different crop microbiota. We thus characterized the microbiota of six birds from the Cojedes and Orinoco Rivers using the G2 PhyloChip and, in parallel, we compared plant availability and foraging behavior of the hoatzins from the two locations. Plant composition differed between the 2 locations, which shared 5 out of 18 plant families and 1 plant genus--Coccoloba--that was highly consumed in both locations. The PhyloChip detected ∼1600 phylotypes from 42 phyla. There was a core microbiota with ~50% of the OTUs shared by at least 4 of the 6 individuals, but there were also differences in the crop microbiota of animals from the two regions. There existed a higher relative abundance of Alphaproteobacteria and Actinobacteria in the crops of birds from the Cojedes River and of Clostridia and Deltaproteobacteria in the crops of birds from the Orinoco River. The results showed both a core crop microbiota and also the bacterial taxa responsible for geographical differences among individuals from the two locations with different vegetation, suggesting an effect of both diet and geography in shaping the crop bacterial community of the hoatzin.