Developmental microbial ecology of the crop of the folivorous hoatzin

Abstract

The hoatzin (Opisthocomus hoazin) is a South American strict folivorous bird, with a crop microbial ecosystem that ferments dietary plants. Chicks progressively become independent from the adultfed regurgitated crop liquids, and we hypothesized that the crop bacterial ecosystem develops through ecological succession mechanisms, as they grow into adults. The aim of this work was to compare the crop bacterial community in hoatzins from three age groups: newly hatched chicks, juveniles and adults by sequencing 16S rRNA genes and using the G2 PhyloChip. Cloning yielded a total of 2123 nearly full-length sequences binned into 294 operational taxonomic units (OTUs) (with o97% homology) belonging to 7 phyla, with 91% of novel OTUs. The microarray identified a diverse bacterial community dominated by Firmicutes and Bacteroidetes, with B1400 taxa grouped in 40 phyla that included those detected by cloning. In comparison with the adult, the hoatzin chick crop had a greater abundance of Flavobacteriaceae, Clostridiaceae and Lachnospiraceae but lacked phyla DSS1, Deferribacteres and Termite group 1, which were mostly present in adults. The overall community structure of the crop of the hoatzin changes with age in a complex manner, probably responding to new niches made available through dietary changes related to the transition from dependent to independent feeding.

Gut Bacterial Diversity of the House Sparrow (Passer domesticus) Inferred by 16S rRNA Sequence Analysis

“…We found that in the first section there was a greater proportion of Proteobacteria, with this group decreasing its relative abundance toward the final region of the intestine, where Firmicutes represented a higher percentage of the sequences. While other studies indicate that the bacterial intestinal communities were dominated by Firmicutes (in the range of 22.6-100%) [3,20] and Bacteroidetes (in the range of 1.1-56%) [19,65], our results show that Firmicutes is the dominant bacterial phylum in the second and third sections of the gut of House Sparrows (Figure 2).…”

“…In the few wild birds that have been studied, bacterial communities were dominated by Firmicutes; however the second dominant phylum varied: Actinobacteria in Adelaide Penguins and Proteobacteria in Zebra-Finches [6,8]. In the Hoatzin (Ophistocomus hoatzin) a folivorous bird with crop microbial fermentation [20], the microbial community of the crop was dominated by Firmicutes and Bacteroidetes [20,21,22] while the bacterial communities of the foregut were dominated by Bacteroidetes and Actinobacteria, and contained a lower proportion of Firmicutes and Proteobacteria [21].…”

Similarities and seasonal variations in bacterial communities from the blood of rodents and from their flea vectors

“…However, the fact that bacterial communities in all gerbil groups have passed through similar seasonal changes suggest that these changes may not be linked to changes in the internal environment of the host. Other studies reported that microbial communities show high variability between host individuals, age groups and sexes and/or a relatively high temporal stability (Moran et al, 2005;Costello et al, 2009;Godoy-Vitorino et al, 2010;Oh et al, 2012;Yatsunenko et al, 2012;Faith et al, 2013;van Dongen et al, 2013;Kueneman et al, 2014;Leclaire et al, 2014). The lack of interindividual variations in the composition of bacterial communities in our study may result from the transmission of fleas between hosts via direct interactions, replacement of burrows or free dispersal (Krasnov, 2008).…”

Diversity and function of the avian gut microbiota

“…However, a recent study on the hoatzin crop, using DNA microarray techniques, documented for the first time the presence of phyla such as Aquificae, Coprothermobacteria, Thermodesulfobacteria and Caldithrix in a vertebrate gut system (Godoy-Vitorino et al 2010). These techniques will need to be replicated on mammalian gut contents to determine if these phyla are unique to the hoatzin crop.…”