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United States Department of Agriculture

Agricultural Research Service

Research Project: Bioavailability of Iron, Zinc and Select Phytochemicals for Improved Health

Location: Plant, Soil and Nutrition Research

Title: The effect of wheat prebiotics on the gut bacterial population and iron status of iron deficient broiler chickens

Authors
item Tako, Elad
item Marija, Knez -
item Glahn, Raymond
item Stangoulis, James -

Submitted to: Nutrition Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 5, 2014
Publication Date: N/A

Interpretive Summary: Background: Currently, there is a lot of interest in improving intestinal health, and consequently increasing iron (Fe) absorption, by managing the intestinal (colonic) beneficial microbial population. This is traditionally done by the consumption of probiotics, live microbial food supplements. However, an alternative, and often very effective approach, is the consumption of food ingredients known as prebiotics. Fructans and arabinoxylans are naturally occurring non-digestible oligosaccharides in wheat that exhibit prebiotic properties and may enhance intestinal Fe absorption. The aim of this study was to assess the effect of prebiotics from wheat on Fe bioavailability in vitro (Caco-2 cells) and in vivo (broiler chickens, Gallus gallus).This research approach may provide additional and vital information in regards to the interactions of intestinal bacterial population, and Fe metabolism and absorption. Methods: In the current study, the effect of intra-amniotic administration of wheat samples extracts at 17 d of embryonic incubation on the Fe status and possible changes in the bacterial population in intestinal content of broiler hatchlings were investigated. A group of 144 eggs were injected with the specified solution (1 ml per egg) into the amniotic fluid (as the amniotic fluid naturally consumed by the embryo). Immediately after hatch (21 d) and from each treatment group, 10 chicks were euthanized and their small intestine, liver and cecum were removed for relative mRNA abundance of intestinal Fe related transporters, relative liver ferritin amounts and bacterial analysis of cecal content, respectively. Results: The in vivo results are in agreement with the in vitro observations, showing no differences in the hatchling Fe status between the treatment groups, as Fe bioavailability was not increased in vitro and no significant differences were measured in the intestinal expression of Fe related transporters and enzyme (DMT1, Ferroportin and DcytB) in vivo. However, there was significant variation in relative amounts of bifidobacteria and lactobacilli in the intestinal content between the treatments groups, with generally more bifidobacteria being produced with increased prebiotic content. Conclusions: In this study we showed that prebiotics naturally found in wheat grains/bread products significantly increased intestinal beneficial bacterial population in Fe deficient broiler chickens. With this short-term feeding trial we were not able to show differences in the Fe-status of broilers. Nevertheless, the increase in relative amounts of bifidobacteria and lactobacilli in the presence of wheat prebiotics is an important finding as these bacterial populations may affect Fe bioavailability in long-term feeding studies. This research is extremely relevant in developing wheat lines that may contain increased amounts of prebiotics, and by that aid in the constant battle of dietary Fe deficiency and anemia.

Technical Abstract: In recent years, there is a lot of interest in improving the intestinal health, and consequently increasing minerals as iron absorption, by managing the intestinal microbial population. This is traditionally done by the consumption of probiotics, which are live microbial food supplements. However, an alternative, and often very effective approach, is the consumption of food ingredients known as prebiotics. Fructans and arabinoxylans are naturally occurring non-digestible oligosaccharides (“prebiotics”) in wheat that exhibit prebiotic properties and may enhance intestinal iron (Fe) absorption. The aim of this study was to assess the effect of prebiotics from wheat on iron bioavailability by using a cellular model (intestinal cells) and animal (broiler chickens) models. Methods: In the current study, the effect of intra-amniotic administration (injection into the developing chicken embryo amniotic fluid) of wheat samples extracts at 17 days of embryonic incubation on the Fe status and possible changes in the bacterial population in intestinal content of broiler hatchlings were investigated. A group of 144 eggs were injected with the specified solution (1 ml per egg) into the amniotic fluid. Immediately after hatch (21 d) and from each treatment group, 10 chicks were euthanized and their small intestine, liver and cecum were removed for relative gene expression analyses of intestinal Fe related proteins, relative liver ferritin (iron storage unit) amounts and bacterial analysis of intestinal content, respectively. Results: The animal model results are in agreement with the cellular model observations, showing no differences in the hatchling Fe status between the treatment groups, as Fe bioavailability was not increased in the cellular model and no significant differences were measured in the intestinal expression of iron related proteins in the animal model used. However, there was significant variation in relative amounts of bifidobacteria and lactobacilli (beneficial and health promoting bacteria) in the intestinal content between the treatments groups, with generally more bifidobacteria being produced with increased prebiotic content. Conclusions: In this study we showed that prebiotics naturally found in wheat grains/bread products significantly increased intestinal beneficial bacterial population in Fe deficient broiler chickens. With this short-term feeding trial we were not able to show differences in the Fe-status of broilers. Nevertheless, the increase in relative amounts of bifidobacteria and lactobacilli in the presence of wheat prebiotics is an important finding as these bacterial populations may affect Fe bioavailability in long-term studies.

Last Modified: 9/23/2014
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