title: Influence of dietary calcium and phosphorus on urinary calcium in commercial leghorn hens.
abstract: An experiment was conducted to determine the influence of dietary Ca (2, 4, and 6%) and P (.3 and .6% total) on urinary Ca and pH and on plasma Ca++ and inorganic P (Pi) in commercial Leghorn hens. Urine (six hens per treatment) or blood (eight hens per treatment) was collected from hens at 0, 7, 14, and 21 h postoviposition on Days 3 and 10 after its introduction to treatment diets. Low dietary P reduced (P less than or equal to .05) plasma Pi concentrations. The lowest concentration of dietary Ca reduced (P less than or equal to .05) plasma Ca++. Urinary pH and Ca were lowest at 14 h after oviposition. Increasing dietary Ca from 4 to 6% had no influence on urinary Ca excretion when the diet contained .6% P. However, when the diet contained 4% Ca, lowering dietary P (from .6% to .3%) increased urinary Ca significantly. Increasing dietary Ca to 6% in the presence of low dietary P further elevated urinary Ca. Urine was acidic with all diets except with that containing 6% Ca and .3% P at 14 h after oviposition. Results indicate that low dietary P has a greater influence on elevating urinary Ca in laying hens than excess dietary Ca.
authors.affiliation: Department of Poultry Science, Auburn University, Alabama 36849.
authors.forename: K S
authors.initials: KS
authors.lastname: Rao
authors.forename: D A
authors.initials: DA
authors.lastname: Roland
mesh_terms: D000818:Animals; D002118:Calcium / Q000097:blood / Q000652:urine*; D002136:Calcium, Dietary / Q000008:administration & dosage / Q000378:metabolism*; D002645:Chickens / Q000378:metabolism* / Q000652:urine; D005260:Female; D006863:Hydrogen-Ion Concentration; D010058:Oviposition / Q000502:physiology; D010758:Phosphorus / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*
chemical_list: D002136:Calcium, Dietary; D010758:Phosphorus; D002118:Calcium