title: Effect of dietary magnesium level on urinary and faecal excretion of calcium, magnesium and phosphorus in adult, ovariectomized cats.
abstract: Dietary Mg restriction is generally considered to contribute to the prevention of struvite urolithiasis in cats, but its effects on faecal and urinary excretion of Ca and P have not been systematically investigated. The present study seeks to fill the gap. In a 4 x 4-week crossover study, ovariectomized cats were fed on purified diets containing either 0.40, 0.79, 1.59 or 3.17 mmol Mg/MJ (0.19, 0.38, 0.76 and 1.52 g Mg/kg diet). Increasing the dietary Mg level from 0.40 to 3.17 mmol Mg/MJ by the addition of extra MgCO3 raised urinary and faecal excretion of Mg from 0.14 to 0.68 mmol/MJ and from 0.28 to 1.66 mmol/MJ respectively. The 8-fold increase in Mg intake significantly raised urinary excretion of Ca from 0.06 to 0.09 mmol/MJ. Apparent absorption and urinary excretion of P were depressed by 13 and 25% respectively when the dietary Mg level was raised from 0.40 to 3.17 mmol/MJ. A dietary level of 0.40 mmol Mg/MJ (0.19 g Mg/kg diet) was found to be sufficient to maintain Mg balance in the adult ovariectomized cats fed on the purified diet.
authors.affiliation: Department of Laboratory Animal Science, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.
authors.forename: F J
authors.initials: FJ
authors.lastname: Pastoor
authors.forename: A T
authors.initials: AT
authors.lastname: Van 't Klooster
authors.forename: R
authors.initials: R
authors.lastname: Opitz
authors.forename: A C
authors.initials: AC
authors.lastname: Beynen
mesh_terms: D000818:Animals; D002118:Calcium / Q000652:urine*; D002415:Cats / Q000652:urine*; D018592:Cross-Over Studies; D005243:Feces; D005260:Female; D008274:Magnesium / Q000008:administration & dosage* / Q000652:urine*; D010052:Ovariectomy / Q000662:veterinary; D010758:Phosphorus / Q000652:urine*
chemical_list: D010758:Phosphorus; D008274:Magnesium; D002118:Calcium