Using the domestic chicken (Gallus gallus) as an in vivo model for iron bioavailability

Poult Sci. 2010 Mar;89(3):514-21. doi: 10.3382/ps.2009-00326.

Abstract

Iron fortification of foods and biofortification of staple food crops are strategies that can help to alleviate Fe deficiency. The broiler chicken may be a useful model for initial in vivo screening of Fe bioavailability in foods due to its growth rate, anatomy, size, and low cost. In this study, we assess the broiler as a model for hemoglobin (Hb) maintenance studies and present a unique duodenal loop technique for direct measurement of intestinal Fe absorption. One-week-old chicks were allocated into Fe-deficient versus Fe-adequate treatment groups. For 6 wk, blood Hb, feed consumption, and BW were measured. At wk 7, birds were anesthetized and their duodenal loops were exposed. The loop was isolated and a nonocclusive catheter was inserted into the duodenal vein for blood sampling. A stable isotope solution containing (58)Fe (1 mg of Fe in 10 mM ascorbic acid) was injected into the loop. Blood samples were collected every 5 min and for 120 min postinjection and analyzed by inductively coupled argon-plasma mass spectrometry for (58)Fe concentrations. In the low-Fe group, Hb concentrations, total body Hb Fe, and BW were lower and Hb maintenance efficiency (indicator for dietary Fe availability) was higher than in the high-Fe group (P < 0.05). Iron absorption was higher in the Fe-deficient birds (P < 0.05). In addition, expression of proteins involved in Fe uptake and transfer [i.e., divalent metal transporter 1 (Fe uptake transporter), ferroportin (involved in Fe transport across the enterocyte), and duodenal cytochrome B reductase (reduces Fe at brush border membrane)] were elevated in the low-Fe group. These results indicate that this model exhibits the appropriate responses to Fe deficiency and has potential to serve as a model for Fe bioavailability. Such a model should be most useful as an intermediate test of in vivo Fe bioavailability observations in preparation for subsequent human studies.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Absorptiometry, Photon
  • Animals
  • Biological Availability*
  • Caco-2 Cells
  • Cation Transport Proteins / genetics
  • Cation Transport Proteins / metabolism
  • Chickens* / growth & development
  • Cytochrome b Group / genetics
  • Cytochrome b Group / metabolism
  • DNA, Complementary / genetics
  • DNA, Complementary / metabolism
  • Food Analysis
  • Gene Expression Regulation / physiology
  • Hemoglobins
  • Humans
  • Intestine, Small / metabolism
  • Iron / administration & dosage
  • Iron / pharmacokinetics*

Substances

  • Cation Transport Proteins
  • Cytochrome b Group
  • DNA, Complementary
  • Hemoglobins
  • metal transporting protein 1
  • solute carrier family 11- (proton-coupled divalent metal ion transporters), member 2
  • Iron