INFLUENCE OF 4 DIETS ON URIC-ACID METABOLISM AND ENDOGENOUS ACID PRODUCTION IN HEALTHY BEAGLES

Objective-To evaluate the influence of 3 diets used to dissolve or pre vent ammonium urate uroliths in dogs, and a diet formulated for growth , on 24-hour excretions of uric acid, ammonia, net acid, titratable ac id, bicarbonate, and creatinine; 24-hour urine volumes; pH values of 2 4-hour urine samples; plasma uric acid concentration; serum creatinine concentration; and endogenous creatinine clearance values. Design-Ran domized block. Animals-Six reproductively intact female Beagles, 3.9 t o 4.2 years old, weighing 8.5 to 11.1 kg. Procedures-Four diets were e valuated for their ability to dissolve magnesium ammonium phosphate he xahydrate (struvite) uroliths (diet S); to minimize uric acid excretio n (diet U); to minimize clinical signs associated with renal failure ( diet K); and to promote growth in pups (diet P). Each diet was fed for 14 days; then 24-hour urine samples were collected. An adult maintena nce diet was fed during a 7-day washout period. Results-Consumption of diet U was associated with lowest plasma uric acid concentration, low est 24-hour urinanry uric acid, ammonia, titratable acid, and net acid excretions, lowest endogenous creatinine clearance values, highest 24 -hour urinary bicarbonate excretion and urine pH values, and highest 2 4-hour urine volumes. Consumption of diet P was associated with opposi te results; results of consumption of diets S and K were intermediate between those for diets U and P. Conclusion-Consumption of diet U by h ealthy Beagles is associated with reduced magnitude of urinary excreti on of uric acid and ammonia, with alkaluria, and with polyuria, which may be beneficial in the management of ammonium urate uroliths in dogs . Clinical Relevance-Results support use of diet U for management of a mmonium urate urolithiasis in dogs.