title: Supplementing corn-soybean meal diets with microbial phytase maximizes phytate phosphorus utilization by weanling pigs.
abstract: Two experiments were conducted with crossbred weanling pigs to determine the optimal dietary supplement of Aspergillus niger phytase activity to a low-P, corn-soybean meal basal diet (BD). In Exp. 1, 50 pigs (7.61 +/- .56 kg BW) received the BD supplemented with 750, 1,050, 1,250, or 1,350 phytase units (PU)/g, or .21% P as mono-dibasic calcium phosphate (MDCaP) for 4 wk. In Exp. 2, 12 pigs (6.39 +/- .74 kg BW) were individually housed in metabolism cages and received BD, BD plus the optimal phytase activity (1,200 PU/g), or BD plus .21% P as MDCaP for 2 wk. In Exp. 1, additions of phytase > 1,050 PU/g of BD did not improve ADG, ADFI, gain/feed, or plasma AP activity. Quadratic relationships between dietary phytase activity and these measures were found and their stationary points were at approximately 1,200 PU/g of BD. Estimated maximum responses of these measures in pigs fed phytase were > or = 90% compared with MDCaP. Pigs fed 1,250 PU/g of BD maintained normal plasma P and Ca concentrations. In Exp. 2, pigs that received 1,200 PU/g of BD utilized dietary P more effectively (P < .05) than pigs fed the BD or the BD plus MDCaP. Although they consumed 44% less P per day, these pigs retained only 7% less P than pigs that received MDCaP. One thousand units of phytase activity supported retention of 1.1 mg of P from the BD, and this level of phytase supplementation was equivalent in effect to .91 mg of P from MDCaP.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Animal Science, Michigan State University, East Lansing 48824.
authors.forename: X G
authors.initials: XG
authors.lastname: Lei
authors.forename: P K
authors.initials: PK
authors.lastname: Ku
authors.forename: E R
authors.initials: ER
authors.lastname: Miller
authors.forename: M T
authors.initials: MT
authors.lastname: Yokoyama
authors.forename: D E
authors.initials: DE
authors.lastname: Ullrey
mesh_terms: D010832:6-Phytase / Q000008:administration & dosage / Q000378:metabolism*; D000469:Alkaline Phosphatase / Q000097:blood; D000821:Animal Feed; D000818:Animals; D001234:Aspergillus niger / Q000201:enzymology; D002118:Calcium / Q000097:blood; D002136:Calcium, Dietary / Q000008:administration & dosage; D004435:Eating; D005260:Female; D008297:Male; D010758:Phosphorus / Q000097:blood; D016226:Phosphorus, Dietary / Q000008:administration & dosage / Q000493:pharmacokinetics*; D010833:Phytic Acid / Q000008:administration & dosage / Q000493:pharmacokinetics*; D011897:Random Allocation; D012044:Regression Analysis; D013025:Glycine max; D013552:Swine / Q000254:growth & development / Q000378:metabolism*; D014886:Weaning; D015430:Weight Gain; D003313:Zea mays; D015032:Zinc / Q000097:blood
chemical_list: D002136:Calcium, Dietary; D016226:Phosphorus, Dietary; D010758:Phosphorus; D010833:Phytic Acid; D000469:Alkaline Phosphatase; D010832:6-Phytase; D015032:Zinc; D002118:Calcium