title: Phytase improves iron bioavailability for hemoglobin synthesis in young pigs.
abstract: Dietary phytase supplementation improves bioavailabilities of phytate-bound minerals such as P, Ca, and Zn to pigs, but its effect on Fe utilization is not clear. The efficacy of phytase in releasing phytate-bound Fe and P from soybean meal in vitro and in improving dietary Fe bioavailability for hemoglobin repletion in young, anemic pigs was examined. In Exp. 1, soybean meal was incubated at 37 degrees C for 4 h with either 0, 400, 800, or 1,200 units (U) of phytase/kg, and the released Fe and P concentrations were determined. In Exp. 2, 12 anemic, 21-d-old pigs were fed either a strict vegetarian, high-phytate (1.34%) basal diet alone, or the diet supplemented with 50 mg Fe/kg diet (ferrous sulfate) or phytase at 1,200 U/kg diet (Natuphos, BASF, Mt. Olive, NJ) for 4 wk. In Exp. 3, 20 anemic, 28-d-old pigs were fed either a basal diet with a moderately high phytate concentration (1.18%) and some animal protein or the diet supplemented with 70 mg Fe/kg diet, or with one of two types of phytase (Natuphos or a new phytase developed in our laboratory, 1,200 U/kg diet) for 5 wk. In Exp. 2 and 3, diets supplemented with phytase contained no inorganic P. In Exp. 1, free P concentrations in the supernatant increased in a phytase dose-dependent fashion (P<.05), whereas free Fe concentrations only increased at the dose of 1,200 U/kg (P<.10). In Exp. 2 and 3, dietary phytase increased hemoglobin concentrations and packed cell volumes over the unsupplemented group; these two measures, including growth performance, were not significantly different than those obtained with dietary supplemental Fe. In conclusion, both sources of phytase effectively degraded phytate in corn-soy diets and subsequently released phytate-bound Fe from the diets for hemoglobin repletion in young, anemic pigs.
authors.affiliation: Department of Animal Science, Cornell University, Ithaca, NY, USA.
authors.forename: C H
authors.initials: CH
authors.lastname: Stahl
authors.forename: Y M
authors.initials: YM
authors.lastname: Han
authors.forename: K R
authors.initials: KR
authors.lastname: Roneker
authors.forename: W A
authors.initials: WA
authors.lastname: House
authors.forename: X G
authors.initials: XG
authors.lastname: Lei
mesh_terms: D010832:6-Phytase / Q000378:metabolism*; D000375:Aging / Q000378:metabolism; D000821:Animal Feed; D000818:Animals; D001682:Biological Availability; D006454:Hemoglobins / Q000096:biosynthesis*; D007501:Iron / Q000493:pharmacokinetics*; D013025:Glycine max; D013552:Swine / Q000378:metabolism*
chemical_list: D006454:Hemoglobins; D007501:Iron; D010832:6-Phytase