Iron Utilization and Metabolism in the Chick

Abstract

Experiments were conducted with chicks to determine whether the iron-containing tissues and tissue enzymes show iron deficiency before a reduction in hemoglobin and packed cell volume is obtained. The results indicate that these latter parameters were reduced earlier than myoglobin level, ferritin and hemosiderin iron levels and cytochrome c and succinic dehydrogenase activities. Iron deficiency in the chick was characterized by poor growth, and reduction in hemoglobin, packed cell volume, myoglobin, ferritin, hemosiderin and succinic dehydrogenase activity. The amount of hemosiderin iron exceeded the amount of ferritin iron in both deficient and normal chicks. The ratio of hemoglobin to ferritin plus hemosiderin indicated that after 3 weeks the iron stored in the liver was being utilized for hemoglobin formation by the iron-deficient chick. Nitrilotriacetic acid (NTA) and ethylenediaminetetraacetic acid (EDTA), combined equimolarly with iron, had little if any effect on body weight, hemoglobin, packed cell volume, myoglobin and ferritin and hemosiderin-iron in the liver or succinic dehydrogenase activity. When NTA and EDTA were fed in the uncomplexed form in the basal diet or in the diet with 10 mg/kg of added iron, the values for hemoglobin and packed cell volume indicated that the former compound improved iron utilization slightly and EDTA interfered with it somewhat. When body weight, hemoglobin and packed cell volume were used as the criteria, the chick's requirement for iron was found to be 79.0, 77.5 and 77.0 mg/kg of diet, respectively. A realistic estimate of the chick's requirement for iron is, therefore, 75 to 80 mg iron/kg of diet. No evidence was obtained that the soybean protein basal diet reduced the utilization of iron. Thus, the possibility that the phytic acid in the soybean protein interfered with the availability of iron was ruled out.