Effects of modified protein diets in dogs with chronic renal failure

A maintenance diet containing 44.4% dry weight protein and 2 reduced protein diets containing 17.2% and 8.2% dry weight protein were studied in dogs with induced chronic renal failure to determine effects on their (1) clinical status, (2) renal function, (3) electrolyte and acid-base balance, (4) divalent ion balance, (5) nutritional status, (6) hematologic status, and (7) hemostasis. A cross-over design of feeding was utilized so that the effect of diet could be studied in each dog at a known state of renal dysfunction and so that reversibility of effects could be determined. The inulin clearance rate was higher when the 44.4% protein diet was fed than when the 8.2% or 17.2% protein diets were fed. However, consumption of lower protein diets was associated with greater physical activity and reduction in serum urea nitrogen concentrations, compared with consumption of the 44.4% protein maintenance diet. Varying degrees of hyperchloremic metabolic acidosis developed in dogs fed the 8.2% and 17.2% protein diets. Reduced total serum protein and albumin concentrations, and hypercholesterolemia developed in dogs fed the 8.2% protein diet. All effects were reversible after diets were changed. It was concluded that diet-induced alterations in renal function associated with moderate dietary protein restriction did not adversely effect clinical and biochemical status of dogs with renal failure. It was unclear whether the clinical and biochemical changes observed with more severe protein restriction resulted from diet-induced changes in renal function.