Diets containing naturally occurring iron or naturally occurring iron plus supplemental ferrous sulfate both maintain normal hematological status in adult dogs

Abstract

Iron is an essential mineral for dogs due to its roles in physiological processes. The NRC recommends the adequate intake for iron in adult dogs is 0.5 mg/kg of body weight. While iron should be present in high enough concentrations in the diet to maintain normal hematological status and prevent iron deficiency anemia, too much dietary iron can increase lipid oxidation in the food during preparation and storage, subsequently reducing shelf life, palatability, and nutritional content of foods. In general, iron is supplemented to diets to ensure that no dogs are deficient. The primary objective of this study was to investigate the ability of a diet containing either 0 mg/kg or 80 mg/kg supplemental iron to support normal hematological parameters in adult dogs. Twenty-two adult dogs were randomly assigned to one of two treatment diets: Test Diet 1, Experimental maintenance formula with 115 mg/kg endogenous iron + 0 mg/kg supplemental iron; and Test Diet 2, Experimental maintenance formula with 115 mg/kg endogenous iron + 80 mg/kg supplemental iron (ferrous sulfate). Dogs consumed treatment diets for 26 weeks, with clinical assessments (e.g., hemoglobin concentration/total iron binding capacity) assessed throughout the trial (0, 2, 4, and 6 months). Baseline iron related endpoints were not different between diet treatments (P > 0.50), except for mean corpuscular hemoglobin concentrations (P = 0.046). No differences were found for iron related end points between the two diet treatments (P>0.05) at any time point. In some diets no supplemental iron will be needed, based on the diet matrix, whereas others may require some supplemental iron. By reducing iron inclusion in the formulations of canine diets, food stability and shelf life may be improved. This reduction in supplemental iron can also reduce cost of formulation, benefiting food manufacturers, consumers, and adult dogs.