title: Digestive morphology and enzyme activity in the Andean toad Bufo spinulosus: hard-wired or flexible physiology?
abstract: Gut plasticity is a trait with implications on animal performance. However, and despite their importance as study models in physiology, research on gut flexibility in amphibians is scarce. In the present work, we analyse digestive adjustments of Bufo spinulosus adult individuals to cope with changes in diet quality and quantity at two organizational levels (i.e., digestive morphology and enzymes). We found that changes in gut size are related to the amount of food ingested, but not to diet composition. This is in agreement with "the gut seasonal change" hypothesis and offers a proximal explanation for this change. Digestive enzymatic activity (maltase and aminopeptidase-N) did not change with diet quality or quantity, which agrees with the hypothesis of "hard-wired physiology in adult amphibians". Both hypotheses are in agreement with the general theoretical framework of gut phenotypic flexibility when interpreted in light of amphibian natural history. In addition, our results indicate that the correlation between feeding frequency and the level of gut up-regulation proposed for interspecific comparisons may also be found at the intraspecific level.
authors.affiliation: Center for Advanced Studies in Ecology and Biodiversity and Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 6513677, Chile.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Naya
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Farfán
authors.forename: Pablo
authors.initials: P
authors.lastname: Sabat
authors.forename: Marco A
authors.initials: MA
authors.lastname: Méndez
authors.forename: Francisco
authors.initials: F
authors.lastname: Bozinovic
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D002025:Bufonidae / Q000033:anatomy & histology / Q000502:physiology*; D018826:CD13 Antigens / Q000378:metabolism; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D004064:Digestive System / Q000033:anatomy & histology* / Q000201:enzymology; D005215:Fasting; D000520:alpha-Glucosidases / Q000378:metabolism
chemical_list: D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D000520:alpha-Glucosidases; D018826:CD13 Antigens