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Urinary relative supersaturations of calcium oxalate and struvite in cats are influenced by diet

Authors :
Smith, Brigitte H.E.
Stevenson, Abigail E.
Markwell, Peter J.
Source :
The Journal of Nutrition. Dec, 1998, Vol. 128 Issue 12, p2763S, 2 p.
Publication Year :
1998

Abstract

Acidification of urine through dietary modification is considered to be the cornerstone for the management and prevention of struvite (magnesium ammonium phosphate) urolithiasis in cats (Taton et al. 1984). Urinary acidification, however, may be a risk factor for calcium oxalate urolithiaisis (Kirk et al. 1995, Osborne et al. 1995). The aim of this study was to compare the effect of commercial dry cat foods on urinary pH, and struvite and calcium oxalate relative supersaturation (RSS), the ultimate determinant of crystallization. Materials and methods. Nine different dry cat foods were fed to groups of six healthy, adult domestic short-haired cats 29 neutered females and 25 neutered males) for periods of between 14 and 21 d. Food allowances were calculated on the basis of an assumed maintenance requirement of 250 kJ/(kg body weight [multiplied by] d); the daily allowance was fed as two meals at 0800 and 1530 h. The cats were housed individually throughout each trial. All housing conditions and procedures fell within the UK Home Office regulations. During the last week of each trial, a 48-hour urine collection was made over dry ice to ensure rapid freezing of the samples. At the end of the collection period, the samples were thawed, and volume and pH were measured. The samples were acidified to pH 2 with hydrochloric acid and frozen for further analysis. Urine concentrations of sodium, potassium, magnesium, calcium, chloride, sulfate, phosphate, oxalate, citrate, pyrophosphate, ammonium and uric acid were analyzed by HPLC. A computer program, Equil 2 (Werness et al. 1985), was used to calculate urinary RSS for struvite and calcium oxalate from the concentrations of these analytes. This resulted in one struvite and one calcium oxalate RSS value for each cat during each trial. RSS is calculated from the activity product of the sample divided by the solubility product for the crystal in question; thus, values of KEY WORDS: cats, feline, urine pH, relative supersaturation, dry cat food

Details

ISSN :
00223166
Volume :
128
Issue :
12
Database :
Gale General OneFile
Journal :
The Journal of Nutrition
Publication Type :
Academic Journal
Accession number :
edsgcl.53643426