title: Hypercalciuric response to dietary supplementation with DL-methionine and ammonium sulfate.
abstract: Renal Ca and inorganic P (Pi) excretion were evaluated in Single Comb White Leghorn pullets reared on diets containing 1 or 3.5% Ca alone or supplemented with .6% DL-methionine or .53% ammonium sulfate. Plasma and urine samples were collected during a CONTROL period, and while 200 mM Ca was infused intravenously (Ca-LOADING). Excess Ca, whether supplied chronically in the feed or infused acutely into birds fed 1% Ca diets, significantly reduced glomerular filtration rates, effective renal plasma flow rates, and Pi excretion rates and significantly increased Ca excretion rates and urine pH. Birds fed diets supplemented with DL-methionine and ammonium sulfate maintained significantly lower plasma Ca concentrations during the CONTROL and Ca-LOADING periods than birds fed the respective 1 or 3.5% Ca basal diets. When compared with birds fed the respective 1 or 3.5% Ca basal diets, birds fed the 1% Ca diet supplemented with ammonium sulfate or the 3.5% Ca diet supplemented with DL-methionine had significantly higher absolute urinary Ca excretion rates during Ca-LOADING. Fractional Ca excretion during Ca-LOADING was significantly higher in birds fed 3.5% Ca supplemented with DL-methionine or ammonium sulfate than in birds fed the 3.5% Ca basal diet. These results indicate that DL-methionine and ammonium sulfate accelerated urinary Ca excretion and reduced Ca retention in the extracellular fluid. The hypercalciuric efficacies of DL-methionine and ammonium sulfate were revealed only when the filtered load of Ca was increased through intravenous Ca infusions.
authors.affiliation: Department of Poultry Science, Pennsylvania State University, University Park 16802.
authors.forename: A J
authors.initials: AJ
authors.lastname: Lent
authors.forename: R F
authors.initials: RF
authors.lastname: Wideman
mesh_terms: D000645:Ammonium Sulfate / Q000008:administration & dosage*; D000818:Animals; D002118:Calcium / Q000097:blood / Q000652:urine*; D002136:Calcium, Dietary / Q000008:administration & dosage* / Q000493:pharmacokinetics; D002645:Chickens / Q000502:physiology* / Q000652:urine; D005260:Female; D005527:Food, Fortified; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D007668:Kidney / Q000187:drug effects / Q000502:physiology*; D008715:Methionine / Q000008:administration & dosage*; D010758:Phosphorus / Q000097:blood / Q000652:urine*; D017595:Renal Plasma Flow / Q000187:drug effects
chemical_list: D002136:Calcium, Dietary; D010758:Phosphorus; D008715:Methionine; D000645:Ammonium Sulfate; D002118:Calcium