title: Using the domestic chicken (Gallus gallus) as an in vivo model for iron bioavailability.
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.
authors.affiliation: Department of Science, Cornell University, Ithaca, NY 14853, USA. et79@cornell.edu
authors.forename: E
authors.initials: E
authors.lastname: Tako
authors.forename: M A
authors.initials: MA
authors.lastname: Rutzke
authors.forename: R P
authors.initials: RP
authors.lastname: Glahn
mesh_terms: D015502:Absorptiometry, Photon; D000818:Animals; D001682:Biological Availability; D018938:Caco-2 Cells; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism; D002645:Chickens / Q000254:growth & development; D003573:Cytochrome b Group / Q000235:genetics / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D005504:Food Analysis; D005786:Gene Expression Regulation / Q000502:physiology; D006454:Hemoglobins; D006801:Humans; D007421:Intestine, Small / Q000378:metabolism; D007501:Iron / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000098742:Ferroportin; D000099236:Solute Carrier Family 11, Member 2
chemical_list: D027682:Cation Transport Proteins; D003573:Cytochrome b Group; D018076:DNA, Complementary; D006454:Hemoglobins; D007501:Iron; D000098742:Ferroportin; D000099236:Solute Carrier Family 11, Member 2