| Effect of age and diet on total and paracellular glucose absorption in nestling house sparrows. | |
| | |
MedLine Citation:
|
PMID: 20337530 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Size and hydrolytic activity of the gastrointestinal tracts of altricial birds undergo large and rapid changes during ontogeny. However, nothing is known about the development of the capacity of absorption of products of digestion, a factor that can limit total digestive performance. Using pharmacokinetic methods applied to wild-collected and laboratory-raised altricial nestlings of house sparrows (Passer domesticus), we addressed several questions of general significance about absorption in young birds. We found that both rate and efficiency of absorption of radiolabeled 3-O-methyl-D-glucose (3-OMD-glucose; absorbed by both transporter-mediated and nonmediated mechanisms) increased significantly between days 3 and 12 posthatch. We hypothesize that these changes can explain improvements in whole-diet digestion rate and efficiency observed in the young of house sparrows and of many other avian species, even after intestinal growth has ceased. We also tested the hypothesis that a high level of nonmediated, paracellular glucose absorption, as is typical in adult house sparrows, would already be observed in nestlings, and that their glucose absorption efficiency would not depend on glucose load because absorption rate is nonsaturable and is matched to substrate concentration. Using l-glucose (which is absorbed by nonmediated mechanism[s]), we found that, as predicted, paracellular absorption accounted for the majority of total absorption in nestlings of all ages, and starch content (0% vs. 25%) in the diet of laboratory-raised nestlings had no effect on efficiency of absorption of 3-OMD-glucose. Presumably, reliance on nonmediated absorption in young sparrows can save energy for growth. Also, during the transition from an almost starch-free, insect-based diet during the first days posthatch to the starch-rich, seed-based diet that is typical of adults, reliance on passive absorption is advantageous because the rate of absorption can easily match the current carbohydrate level in the intestines and the activity of hydrolytic enzymes. |
| | |
Authors:
|
Paweł Brzek; Enrique Caviedes-Vidal; Keeshia Hoefer; William H Karasov |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S. |
Journal Detail:
|
Title: Physiological and biochemical zoology : PBZ Volume: 83 ISSN: 1537-5293 ISO Abbreviation: Physiol. Biochem. Zool. Publication Date: 2010 May-Jun |
Date Detail:
|
Created Date: 2010-04-15 Completed Date: 2010-07-20 Revised Date: - |
Medline Journal Info:
|
Nlm Unique ID: 100883369 Medline TA: Physiol Biochem Zool Country: United States |
Other Details:
|
Languages: eng Pagination: 501-11 Citation Subset: IM |
Affiliation:
|
Department of Forest and Wildlife Ecology, University of Wisconsin, 1630 Linden Drive, Madison, Wisconsin 53706, USA. brzek@uwb.edu.pl |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Absorption Adaptation, Physiological Aging / physiology* Animals Area Under Curve Body Weight Diet Glucose / metabolism*, pharmacokinetics Intestine, Small / anatomy & histology, physiology Models, Biological Sparrows / physiology* |
| Chemical | |
Reg. No./Substance:
|
50-99-7/Glucose |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Energetics of Hypoxia in a Mouth-Brooding Cichlid: Evidence for Interdemic and Developmental Effects...
Next Document: Insights into the Mechanisms of Toxicity and Tolerance to the Agricultural Fungicide Mancozeb in Yea...