Impact of Supplements on Iron Absorption From Diets Containing High and Low Iron Concentrations in the European Starling (Sturnus vulgaris)

Abstract Iron absorption was compared in European starlings (Sturnus vulgaris) fed diets containing high iron (1585 ppm), high iron (1720 ppm) with a phytate (inosital) and tannic acid, low iron (32–34 ppm), low iron with a meat-based dog food, or low iron with vitamin C. Iron absorption was determined by colorimetric analysis of nonheme liver iron. A dietary iron concentration of 32 ppm was inadequate to meet the physiologic demands of the starlings, even when vitamin C or a meat-based dog food was added. The high-iron diet caused an increase in concentrations of nonheme liver iron to levels similar to those in birds that have died of iron storage disease (ISD). Nonheme liver iron concentrations did not increase when a phytate (inositol) and tannic acid were added the high-iron diet. The optimal dietary iron concentration for starlings was narrowed to the range of 34–125 ppm. Adding a phytate, tannic acid, or both to readily available food stuffs may be a practical alternative to more expensive low-iron ...