Title
Functional characterization of folic acid transport in the intestine of the laying hen using the everted intestinal sac model
Date Issued
01 January 2011
Access level
open access
Resource Type
journal article
Author(s)
Tactacan G.B.
Karmin O.
House J.D.
University of Manitoba
Publisher(s)
Oxford University Press
Abstract
Absorption at the level of the intestine is likely a primary regulatory mechanism for the deposition of dietary supplemented folic acid into the chicken egg. Therefore, factors affecting the intestinal transport of folic acid in the laying hen may influence the level of egg folate concentrations. To this end, a series of experiments using intestinal everted sacs were conducted to characterize intestinal folic acid absorption processes in laying hens. Effects of naturally occurring folate derivatives(5-methyl and 10-ormyltetrahydrofolate) as well as heme on folic acid absorption were also investigated. Folic acid absorption was measured based on the rate of uptake of 3H-labeled folic acid in the everted sac from various segments of the small and large intestines. Folic acid concentration, incubation length, and pH condition were optimized before the performance of uptake experiments. The distribution profile of folic acid transport along the intestine was highest in the upper half of the small intestine. Maximum uptake rate (nmol.100 g tissue-1.min-1) was observed in the duodenum (20.6 ± 1.9) and jejunum (22.3 ± 2.0) and decreased significantly in the ileum (15.3 ± 1.1) and cecum (9.3 ± 0.9). Transport increased proportionately (P < 0.05) between 0.0001 and 0.1 μM folic acid. Above 0.1 μM, the slope of the regression line was not significantly different from zero (P < 0.137). Folic acid uptake in the jejunum showed a maximum rate of transport at pH 6.0, but was lowest at pH 7.5. The presence of 5-methyl and 10-formyltetrahydrofolate as well as heme impeded folic acid uptake, reducing intestinal folic acid absorption when added at concentrations ranging from 0 to 100 μM. Overall, these data indicated the presence of a folic acid transport system in the entire intestine of the laying hen. Uptake of folic acid in the cecum raises the likelihood of absorption of bacterial-derived folate. © 2011 Poultry Science Association Inc.
Start page
83
End page
90
Volume
90
Issue
1
Language
English
OCDE Knowledge area
Crías y mascotas Ciencia veterinaria
Scopus EID
2-s2.0-78650626334
Source
Poultry Science
ISSN of the container
00325791
Sponsor(s)
This research was financially supported through a Collaborative Research and Development Grant from the Natural Sciences and Engineering Research Council of Canada, in collaboration with the Manitoba Egg Farmers (Winnipeg, Manitoba, Canada) and the Egg Farmers of Canada (Ottawa, Ontario, Canada). The help of the following members of the Department of Animal Science, University of Manitoba, is gratefully acknowledged: Gary Crow, Harry Muc, Jerry Levan-doski, Aurele Chartier, Jason Neufeld, and Naveen Gakhar; Bill Diehl-Jones from the Department of Nursing, University of Manitoba, is also acknowledged for his input in determining the cell viability of the everted sac preparations.
Sources of information: Directorio de Producción Científica Scopus