title: Influence of dietary calcium and phytase on phytate phosphorus hydrolysis in broiler chickens.
abstract: The effect of Ca and phytase on phytate phosphorus (PP) hydrolysis was studied in vitro and in vivo. In vitro, PP hydrolysis by a 3-phytase and a 6-phytase was studied at pH 2.5 and 6.5 with Ca added at levels equivalent to 0, 0.1, 0.2, 0.4, 0.7, or 0.9% of the diet. Irrespective of enzyme, Ca at a level as low as 0.1% reduced (P < 0.05) PP hydrolysis at pH 6.5. To test these effects in vivo, 22-d-old male broilers were fed 1 of 6 diets (10 replicate pens of 4 birds per diet) for 30 h. The experimental design was a 3 x 2 factorial arrangement of 3 phytase treatments (0, 500 U of phytase A/kg of diet, and 500 U of phytase B/kg of diet) and 2 added Ca levels (0 and 0.5% from CaCO3) to a corn-soy basal diet. Adding Ca to the diet resulted in a reduction (P < 0.05) in ileal PP disappearance from 69.2 to 25.4% when the 0 and 0.5% added Ca diets were fed, respectively, and in apparent ileal Ca and P absorption (46.3 to 33.6% and 67.9 to 29.4% when 0 and 0.5% Ca were added, respectively). Inclusion of a 3-phytase improved (P < 0.05) ileal PP disappearance from 25.4 to 58.9% in diets containing 0 and 0.5% added Ca, but the improvement was less pronounced with a 6-phytase. Apparent ileal Ca absorption was improved (P < 0.05) when Ca, phytase, or both were added to the diet.
authors.affiliation: Department of Animal and Avian Sciences, University of Maryland College Park, Maryland 20742, USA.
authors.forename: N M
authors.initials: NM
authors.lastname: Tamim
authors.forename: R
authors.initials: R
authors.lastname: Angel
authors.forename: M
authors.initials: M
authors.lastname: Christman
mesh_terms: D010832:6-Phytase / Q000008:administration & dosage* / Q000378:metabolism; D000818:Animals; D001682:Biological Availability; D002136:Calcium, Dietary / Q000008:administration & dosage* / Q000493:pharmacokinetics; D002645:Chickens / Q000378:metabolism*; D004032:Diet; D004063:Digestion; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007408:Intestinal Absorption; D010758:Phosphorus / Q000378:metabolism*; D010833:Phytic Acid / Q000737:chemistry*; D013025:Glycine max; D003313:Zea mays
chemical_list: D002136:Calcium, Dietary; D010758:Phosphorus; D010833:Phytic Acid; D010832:6-Phytase