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

• Published in: Poultry science Vol. 89; no. 3; pp. 514 - 521
• Main Authors: Tako, E, Rutzke, M.A, Glahn, R.P
• Format: Journal Article
• Language: English
• Published: England Poultry Science Association 01.03.2010
• Subjects: Absorptiometry, Photon; animal models; Animals; ascorbic acid; biofortification; Biological Availability; blood chemistry; body weight; broiler chickens; broiler feeding; brush border membrane vesicles; Caco-2 Cells; Cation Transport Proteins - genetics; Cation Transport Proteins - metabolism; Chickens - growth & development; cytochrome b; Cytochrome b Group - genetics; Cytochrome b Group - metabolism; dietary minerals; DNA, Complementary - genetics; DNA, Complementary - metabolism; duodenum; enterocytes; feed intake; Food Analysis; food fortification; fortified foods; Gene Expression Regulation - physiology; hemoglobin; Hemoglobins; Humans; in vivo studies; Intestine, Small - metabolism; iron; Iron - administration & dosage; Iron - pharmacokinetics; mass spectrometry; methodology; nutrient availability; nutrient deficiencies; oxidoreductases; transport proteins
• ISSN: 0032-5791; 1525-3171
• DOI: 10.3382/ps.2009-00326

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 ⁵⁸Fe (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 ⁵⁸Fe 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.