Effect of iron source on iron absorption and gene expression of iron transporters in the ligated duodenal loops of broilers.

This experiment was conducted to investigate the effect of iron source on Fe absorption and the gene expression of divalent metal transporter 1 (DMT1) and ferroportin 1 (FPN1) in the ligated duodenal loops of broilers. The in situ ligated duodenal loops from Fe-deficient broiler chicks (28-d-old) were perfused with Fe solutions containing 0 to 14.33 mmol Fe/L from 1 of the following: Fe sulfate (FeSO4·7H2O), Fe methionine with weak chelation strength (Fe-Met W; chelation strength is expressed as quotient of formation [Qf] value, Qf = 1.37), Fe proteinate with moderate chelation strength (Fe-Prot M; Qf = 43.6), and Fe proteinate with extremely strong chelation strength (Fe-Prot ES; Qf = 8,590) for up to 30 min. The gene expression of DMT1 and FPN1 in the duodenal loops from the control group and the groups treated with 3.58 mmol Fe/L from 1 of 4 Fe sources was analyzed. The absorption kinetics of Fe from different Fe sources in the duodenum followed a saturated carrier-dependent transport process. The maximum transport rate (Jmax) values in the duodenum were greater (P < 0.03) for Fe-Prot ES and Fe-Prot M than for Fe-Met W and FeSO4·7H2O. The Fe perfusion inhibited (P < 0.05) the mRNA expression of DMT1 but enhanced (P < 0.0008) the mRNA expression of FPN1 in the duodenum and had no effect (P > 0.14) on the protein expression levels of the 2 transporters. These results indicated that organic Fe sources with greater Qf values showed higher Fe absorption; however, all Fe sources followed the same saturated carrierdependent transport process in the duodenum, and DMT1 and FPN1 might participate in Fe absorption in the duodenum of broilers regardless of Fe source. [ABSTRACT FROM AUTHOR]