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COMPLEX EVOLUTION OF BILE SALTS IN BIRDS
Lee R Hagey1, Nicolas Vidal, Alan F Hofmann
1Department of Medicine, University of California at San Diego, San Diego, California, 92093, USA.
The Auk
|November 30, 2010
Summary
This study reveals extensive structural variation in bird bile salts, comparable to mammals and reptiles. These findings offer insights into the evolution of bile salt pathways across diverse avian species.
Area of Science:
- Biochemistry
- Evolutionary Biology
- Zoology
Background:
- Bile salts, cholesterol end-metabolites, are crucial for lipid digestion and gut microbiota.
- Limited research exists on bile salt diversity within avian species.
- Understanding avian bile salt profiles can illuminate evolutionary pathways.
Purpose of the Study:
- To investigate the variation in bile salt composition across a diverse range of bird species.
- To correlate observed bile salt variations with current avian phylogenies.
- To explore hypotheses regarding the evolution of bile salt synthesis pathways in birds.
Main Methods:
- Analyzed the biliary bile salt composition of 405 phylogenetically diverse bird species.
- Included 7 paleognath species in the analysis.
- Compared bile salt profiles across different avian families, diets, and with other vertebrate groups.
Main Results:
- Bile salt profiles demonstrated stability within avian families.
- Complex bile salt profiles were more prevalent in omnivorous and herbivorous birds compared to carnivores.
- Structural variation in bird bile salts is extensive, featuring unique hydroxylations (e.g., at carbon-16) and previously uncharacterized compounds, comparable to reptiles and mammals.
Conclusions:
- Avian bile salt composition exhibits significant structural diversity, mirroring that of other major vertebrate classes.
- The study provides a foundation for inferring evolutionary trajectories of bile salt synthesis pathways, particularly through comparisons with reptiles.
- Extensive hydroxylation at carbon-16 is a distinctive feature of bile salts in birds compared to other vertebrates.
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