title: Effects of copper source and concentration on in vitro phytate phosphorus hydrolysis by phytase.
abstract: Five copper (Cu) sources were studied at pH 2.5, 5.5, and 6.5 to determine how Cu affects phytate phosphorus (PP) hydrolysis by phytase at concentrations up to 500 mg/kg diet (60 min, 40-41 degrees C). Subsequently, Cu solubility with and without sodium phytate was measured. Adding Cu inhibited PP hydrolysis at pH 5.5 and pH 6.5 (P < 0.05). This inhibition was greater with higher concentrations of Cu. Tri-basic copper chloride and copper lysinate inhibited PP hydrolysis much less than copper sulfate pentahydrate, copper chloride, and copper citrate (P < 0.05). A strong negative relationship was observed between PP hydrolysis and soluble Cu at pH 5.5 (r = -0.76, P < 0.0001) and 6.5 (r = -0.54, P < 0.0001). In conclusion, pH, Cu concentration, and source influenced PP hydrolysis by phytase in vitro and were related to the amount of soluble Cu and the formation of insoluble copper-phytin complexes.
authors.affiliation: Department of Animal Science, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Yanfang
authors.initials: Y
authors.lastname: Pang
authors.forename: Todd J
authors.initials: TJ
authors.lastname: Applegate
mesh_terms: D010832:6-Phytase / Q000378:metabolism*; D003300:Copper / Q000032:analysis* / Q000737:chemistry / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D010758:Phosphorus / Q000378:metabolism*; D010833:Phytic Acid / Q000378:metabolism*; D012995:Solubility
chemical_list: D010758:Phosphorus; D003300:Copper; D010833:Phytic Acid; D010832:6-Phytase