Foregut Fermentation in the Hoatzin, a Neotropical Leaf-Eating Bird

@article{Grajal1989ForegutFI,
  title={Foregut Fermentation in the Hoatzin, a Neotropical Leaf-Eating Bird},
  author={Alejandro Grajal and Stuart D. Strahl and R. Parra and Maria Gloria Dominguez and Alfredo Neher},
  journal={Science},
  year={1989},
  volume={245},
  pages={1236 - 1238}
}
The only known case of an avian digestive system with active foregut fermentation is reported for the hoatzin (Opisthocomus hoazin), one of the world's few obligate folivorous (leaf-eating) birds. Hoatzins are one of the smallest endotherms with this form of digestion. Foregut fermentation in a flying bird may be explained by increased digestive efficiency by selection of highly fermentable and extremely patchy resources, coupled with microbial nutritional products and secondary compound… 
Evolutionary significance of foregut fermentation in the hoatzin (Opisthocomus hoazin; Aves: Opisthocomidae)
TLDR
The hoatzin (Opisthocomus hoazin) is the only folivorous bird known to possess extensive fermentation in the crop by mixed bacterial populations, and its significance in the evolution of herbivory in vertebrates is discussed.
Gastric lysozyme as a digestive enzyme in the hoatzin (Opisthocomus hoazin), a ruminant-like folivorous bird
TLDR
It is proposed that the hoatzin expresses a lysozyme which has been recruited to function as a digestive enzyme, representing a unique case of evolutionary convergence of digestive adaptations in this bird and foregut fermenter mammals.
STRUCTURE AND FUNCTION OF THE DIGESTIVE TRACT OF THE HOATZIN (OPISTHOCOMUS HOAZIN): A FOLIVOROUS BIRD WITH FOREGUT FERMENTATION
TLDR
The extreme gut adaptations in the Hoatzin are more similar to those of small mammals with foregut fermentation than to any known bird, which suggests that a similar set of evolutionary constraints may affect the evolution of foreGut fermentation in vertebrates.
Digestive efficiency of the Hoatzin, Opisthocomus hoazin: a folivorous bird with foregut fermentation
TLDR
The high overall digestibility by captive Hoatzins is higher than values previously reported for other avian herbivores but similar to those of foregut-fermenting mammals on similar diets.
Microbial Digestive Symbionts of the Crop of the Hoatzin (Opisthocomus hoazin): An Avian Foregut Fermenter
TLDR
The hoatzin is the only bird known to have a well-developed system of microbial fermentation of plant material (mostly young leaves) in its crop and microbial symbionts appear to play an important role in the nutrition of this bird.
Consumption of toxic plants by the hoatzin
TLDR
The most cytotoxic dietary plants were from Pithecellobium and Pterocarpus genera, and crop bacteria were less inhibited by plant extracts if the corresponding plants were consumed.
Bacterial Community in the Crop of the Hoatzin, a Neotropical Folivorous Flying Bird
TLDR
The hoatzin is unique among known avian species because of the fermentative function of its enlarged crop, and this bird provides an interesting model to examine how diet selection and the gut microbiota contribute to maximizing digestive efficiency.
Developmental microbial ecology of the crop of the folivorous hoatzin
TLDR
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.
Comparative analyses of foregut and hindgut bacterial communities in hoatzins and cows
TLDR
Comparing the community structure of foregut and hindgut bacterial communities in the cow and hoatzin to evaluate the influences of host phylogeny and organ function in shaping the gut microbiome shows that the microbial communities cluster primarily by functional environment (foreguts cluster separately from hindguts) and then by host.
Mutualistic Fermentative Digestion in the Gastrointestinal Tract: Diversity and Evolution1
  • R. Mackie
  • Medicine, Biology
    Integrative and comparative biology
  • 2002
TLDR
The development and application of molecular ecology techniques promises to link distribution and identity of gastrointestinal microbes in their natural environment with their genetic potential and in situ activities.
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