title: Phytate phosphorus hydrolysis as influenced by dietary calcium and micro-mineral source in broiler diets.
abstract: Phytate phosphorus (PP) hydrolysis by a 3-phytase was studied in vitro at pH 2.5 and 6.5 with either 0, 1.0, 4.0, or 9.0 g of Ca/kg diet, or 0, 1.0, 5.0, 7.5, or 10.0 g/kg diet of micro-mineral premix added as inorganic (IMM) or an equivalent level as micro-mineral-amino acid complexes (MAAC). Adding Ca or micro-minerals reduced (P < 0.05) PP hydrolysis at both pHs; however, the effect was greater at pH 6.5. An in vivo experiment was conducted in which broilers were fed one of six diets for 30 h. The experimental design was a factorial of three micro-mineral forms (0 added, IMM, and MAAC) and two Ca levels (0 or 5 g/kg). Adding Ca reduced (P < 0.05) PP disappearance and increased Ca apparent absorption. No micro-minerals effect (P > 0.05) was seen. Therefore, in poultry diets, it is Ca that inhibits PP hydrolysis and decreases P availability.
authors.affiliation: Department of Animal and Avian Sciences, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: Nada M
authors.initials: NM
authors.lastname: Tamim
authors.forename: Roselina
authors.initials: R
authors.lastname: Angel
mesh_terms: D000596:Amino Acids / Q000008:administration & dosage; D000818:Animals; D002136:Calcium, Dietary / Q000494:pharmacology*; D002645:Chickens; D004032:Diet; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008297:Male; D008903:Minerals / Q000008:administration & dosage*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism*; D010833:Phytic Acid / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D002136:Calcium, Dietary; D008903:Minerals; D010758:Phosphorus; D010833:Phytic Acid; D010744:Phosphoric Monoester Hydrolases; C400321:3-phytase