Effects of prebiotic supplementation on the expression of proteins regulating iron absorption in anaemic growing rats

Abstract

Prebiotics may increase intestinal Fe absorption in anaemic growing rats. The present study evaluated the effects of high-performance (HP) inulin and oligofructose on factors that regulate Fe absorption in anaemic rats during the growth phase. Male Wistar rats aged 21 d of age were fed AIN-93G ration without Fe for 2 weeks to induce Fe-deficiency anaemia. The rats were fed on day 35 a control diet, or a diet with 10 % HP inulin, or a diet with 10 % oligofructose, without Fe supplementation. The animals were euthanised after 2 weeks, and segments of the duodenum, caecum, colon and liver were removed. The expression levels of proteins in the intestinal segments were assessed using Western blotting. The levels of serum, urine and liver hepcidin and the concentrations of IL-10, IL-6 and TNF-a in the caecum, colon and liver were measured using the ELISA test. HP inulin increased the expression of the divalent metal transporter 1 protein in the caecum by 162 % (P¼ 0·04), and the expression of duodenal cytochrome b reductase in the colon by 136 % (P¼ 0·02). Oligofructose decreased the expression of the protein ferroportin in the duodenum (P¼0·02), the concentrations of IL-10 (P¼ 0·044), IL-6 (P¼ 0·036) and TNF-a (P¼0·004) in the caecum, as well as the level of urinary hepcidin (P,0·001). These results indicate that prebiotics may interfere with the expression of various intestinal proteins and systemic factors involved in the regulation of intestinal Fe absorption in anaemic rats during the growth phase.

Partially Hydrolyzed Guar Gum Increases Ferroportin Expression in the Colon of Anemic Growing Rats

“…In general, studies [10,12,13,30,31] with different types, associations, and concentrations of prebiotics did not observe any negative effect on iron absorption. In contrast with previous evidence, these soluble fibers increased Hb levels or at the very least did not limit iron absorption.…”

“…Freitas et al [12] also did not find significant differences with the use of PHGG on the growth and body weight of growing rats over a three-week period. Other soluble fibers, such as oligofructose and inulin, also did not affect the growth of the animals [7,10,13]. …”

“…Marciano et al [13], using the same animal model of the present study, assessed the intake of inulin (9.7%) and oligofructose (9.2%) in DMT1, ferroportin, and Dcytb expression. Like PHGG, inulin and oligofructose did not promote a significant increase of these proteins in the duodenum.…”

“…It is used on a large scale in enteral feeding, as a dietary fiber supplement, in drinks and foods, and in the food industry in general [12]. However, little is known about the effect of PHGG on the absorption of minerals and its mechanisms, but recent studies have shown the benefits associated with prebiotic intake on mineral absorption [10,12,13], with no damage to the body growth of the animals. The present study aimed to analyze the effect of PHGG intake on the food intake, body growth, intestinal weight, and ferroportin expression in the intestine and liver of anemic growing rats.…”

Consumption of galacto-oligosaccharides increases iron absorption from a micronutrient powder containing ferrous fumarate and sodium iron EDTA: a stable-isotope study in Kenyan infants

“…In contrast, because FeFum is only acid soluble, and postprandial gastric pH is high in infants (10), FeFum iron may pass into the colon mainly as intact FeFum, where its absorption might be more likely to be enhanced by a GOS-mediated pH decrease. Other mechanisms that may contribute to a prebiotic effect on iron absorption are 1) an increased expression of genes involved in iron absorption (35), 2) changes in colonic mucosal architecture (36), 3) modification of the meal matrix such as changes in viscosity or reducing power, and 4) anti-inflammatory effects in the colon (37) reducing circulating hepcidin (35), but not all studies agree (38).…”