The Effect of Supplemental Phytase on Iron Bioavailability to Weanling Pigs in a Wheat-based Diet

Two experiments were conducted to investigate the effect of supplemental dietary phytase on intrinsic Fe bioavailability in a wheat-based diet fed to anemic weanling pigs. Previous work has shown that supplementing phytase in corn-soybean based diets improves iron bioavailability in the pig model. In Experiment 1, pigs were either fed an iron deficient basal diet or the basal diet supplemented with 2,000 phytase U/kg of feed. In this experiment, weanling pigs had access to a commercial creep feed prior to being fed the experimental diets, and the pigs were initially less anemic than pigs in Experiment 2. Supplemental phytase had no apparent effect on intrinsic iron bioavailability in Experiment 1. In Experiment 2 pigs were fed an iron deficient creep feed and weaning diet prior to being fed one of three experimental diets. In Experiment 2, pigs fed the iron deficient basal diet had lower growth performance, packed cell volume, and blood hemoglobin concentrations than pigs fed the basal diet supplemented with 2,500 phytase U/kg of feed, or the basal diet supplemented with inorganic iron at 40 mg/kg of feed. Phytase supplementation in a wheat-based diet appears to improve intrinsic iron bioavailability, and appears to correct iron deficiency as effectively as supplementing a source of inorganic iron in swine diets. These results highlight the necessity for using sensitive models when investigating nutrient bioavailability. The ability for phytase supplementation to provide an alternative means for preventing and correcting iron deficiency warrants further research