Biology subjects

Trevelline, B. K.

Publications and source records attributed to Trevelline, B. K..

3 recordsLinked to original sources

bioRxiv2026

Gut microbiota promote early-life digestive function in songbirds

The vertebrate digestive tract harbors complex microbial communities whose influences on phenotypes and fitness in non-model organisms remain poorly understood. Here, we show that colonization with gut microbiota is critical for digestive development and function in a non-model songbird, the House sparrow (Passer domesticus). We raised nestlings under sterile (axenic) conditions and compared them to nestlings reconstituted (conventionalized) with microbiota from adult sparrows. Conventionalization drove significant increases in villus length, crypt depth, goblet cell density, and mucosal thickness in the small intestine. Conventionalized nestlings also exhibited increased growth of several digestive organs and elevated circulating bile acid levels, including bacterial metabolites known to promote growth and lipid metabolism in vertebrates. These results reveal functions of songbird microbiota and establish axenic methods for non-model oviparous vertebrates.

microbiology↗

bioRxiv2022

Adaptive remodeling of the gut microbiome over long-distance migration

The gut microbiome can be thought of as a forgotten organ, owing to its profound effects on host phenotypes. Long-distance migratory birds are capable of adaptively modulating their physiology, raising the hypothesis that the microbiome of migratory birds may undergo a parallel remodeling process that helps to meet the energetic demands of long-distance migration. To test this hypothesis, we investigated changes in gut microbiome composition and function over the fall migration of a Neotropical-Nearctic migratory Blackpoll Warbler (Setophaga striata), which exhibits one of the longest known autumnal migratory routes of any songbird and rapidly undergoes extensive physiological remodeling during migration. Overall, our results showed that the Blackpoll warbler microbiome differed significantly across phases of fall migration. This pattern was driven by a dramatic increase in the relative abundance of Proteobacteria, and more specifically a single ASV belonging to the family Enterobacteriaceae. Further, blackpolls exhibited a progressive reduction in microbiome phylogenetic diversity and within-group variances over migration, indicating convergence of microbiome composition among individuals during long-distance migration. Metagenomic analysis revealed that the gut microbiome of staging blackpolls was enriched in bacterial pathways involved in vitamin, amino acid, and fatty acid biosynthesis, as well as carbohydrate metabolism, and that these pathways were in turn positively associated with host body mass and subcutaneous fat deposits. Together, these results provide evidence that the gut microbiome of migratory birds may undergo adaptive remodeling to meet the physiological and energetic demands of long-distance migration.

ecology↗

bioRxiv2020

Microbial control over host diet selection

Diet selection is a fundamental aspect of animal behavior with numerous ecological and evolutionary implications. While the underlying mechanisms are complex, the availability of essential dietary nutrients can strongly influence diet selection behavior. The gut microbiome has been shown to metabolize many of these same nutrients, leading to the untested hypothesis that intestinal microbiota may influence diet selection. Here we show that germ-free mice colonized by gut microbiota from three rodent species with distinct foraging strategies differentially selected diets that varied in macronutrient composition. Specifically, we found that herbivore-conventionalized mice voluntarily selected a higher protein:carbohydrate ratio diet, while omnivore- and carnivore-conventionalized mice selected a lower P:C ratio diet. In support of the long-standing hypothesis that tryptophan - the essential amino acid precursor of serotonin - serves as a peripheral signal regulating diet selection, bacterial genes involved in tryptophan metabolism and plasma tryptophan availability prior to the selection trial were significantly correlated with subsequent voluntary carbohydrate intake. Finally, herbivore-conventionalized mice exhibited larger intestinal compartments associated with microbial fermentation, broadly reflecting the intestinal morphology of their donor species. Together, these results demonstrate that gut microbiome can influence host diet selection behavior, perhaps by mediating the availability of essential amino acids, thereby revealing a novel mechanism by which the gut microbiota can influence host foraging behavior. SIGNIFICANCEThe behavior of diet choice or diet selection can have wide-reaching implications, scaling from individual animals to ecological and evolutionary processes. Previous work in this area has largely ignored the potential for intestinal microbiota to modulate these signals. This notion has been highly speculated for years but has not yet been explicitly tested. Here we show that germ-free mice colonized by differential microbiomes (from wild rodents with varying natural feeding strategies) exhibited significant differences in their voluntary dietary selection. Specifically, differences in voluntary carbohydrate selection were associated with plasma amino acid levels and bacterial genes involved in the metabolism of tryptophan. Together, these results demonstrate a role for the microbiome in host nutritional physiology and behavior.

microbiology↗