title: Short term effects of increasing dietary salt concentrations on urine composition in healthy cats.
abstract: High dietary salt (NaCl) concentrations are assumed to be beneficial in preventing the formation of calcium oxalate (CaOx) uroliths in cats, since increased water intake and urine volume have been observed subsequent to intake. In human beings, dietary NaCl restriction is recommended for the prevention of CaOx urolith formation, since high NaCl intake is associated with increased urinary Ca excretion. The aim of the present study was to clarify the role of dietary NaCl in the formation of CaOx uroliths in cats. Eight cats received four diets that differed in Na and Cl concentrations (0.38-1.43% Na and 0.56-2.52% Cl dry matter, DM). Each feeding period consisted of a 21 day adaptation period, followed by a 7 day sampling period for urine collection. Higher dietary NaCl concentrations were associated with increased urine volume and renal Na excretion. Urinary Ca concentration was constant, but renal Ca excretion increased from 0.62 to 1.05 mg/kg bodyweight (BW)/day with higher dietary NaCl concentrations (P ≤ 0.05). Urinary oxalate (Ox), citrate, P and K concentrations decreased when NaCl intake was high (P ≤ 0.05), and urinary pH was low in all groups (6.33-6.45; P > 0.05). Relative supersaturation of CaOx in the urine was unaffected by dietary NaCl concentrations. In conclusion, the present study demonstrated several beneficial effects of high dietary NaCl intake over a relatively short time period. In particular, urinary Ca concentration remained unchanged because of increased urine volume. Decreased urinary Ox concentrations might help to prevent the formation of CaOx uroliths, but this should be verified in future studies in diseased or predisposed cats.
authors.affiliation: Institute of Animal Nutrition, Department of Veterinary Medicine, Freie Universität Berlin, Königin-Luise-Str. 49, 14195 Berlin, Germany. Electronic address: Nadine.Passlack@fu-berlin.de.
authors.forename: N
authors.initials: N
authors.lastname: Paßlack
authors.affiliation: Institute of Animal Nutrition, Department of Veterinary Medicine, Freie Universität Berlin, Königin-Luise-Str. 49, 14195 Berlin, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Burmeier
authors.affiliation: Mars GmbH, Eitzer Straße 215, 27283 Verden, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Brenten
authors.affiliation: Institute of Biometry and Clinical Epidemiology, Charité, Universitätsmedizin Berlin, Hindenburgdamm 30, 12203 Berlin, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Neumann
authors.affiliation: Institute of Animal Nutrition, Department of Veterinary Medicine, Freie Universität Berlin, Königin-Luise-Str. 49, 14195 Berlin, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Zentek
mesh_terms: D000818:Animals; D002129:Calcium Oxalate / Q000652:urine*; D002371:Cat Diseases / Q000139:chemically induced* / Q000652:urine; D002415:Cats; D004032:Diet / Q000662:veterinary; D004305:Dose-Response Relationship, Drug; D005260:Female; D006863:Hydrogen-Ion Concentration; D008297:Male; D012965:Sodium Chloride / Q000378:metabolism*; D014545:Urinary Calculi / Q000139:chemically induced / Q000652:urine / Q000662:veterinary*; D014556:Urine / Q000737:chemistry*
chemical_list: D002129:Calcium Oxalate; D012965:Sodium Chloride
keywords: Calcium oxalate; Cats; Dietary salt; Renal calcium excretion