Effects of dietary protein/phosphate restriction in normal dogs and dogs with chronic renal failure

The effects of three dietary protein intakes (1–9, 1–3, and 0–6 g protein/kg bodyweight/day) on selected aspects of protein, mineral and electrolyte balance as well as renal functions was studied in normal dogs with moderate chronic renal failure. Dietary phosphate levels varied according to the quantity of phosphate in protein sources. Within the ranges of protein intake examined in this study, protein intake did not have a significant effect on glomerular filtration rates as measured by inulin clearance or 24‐hour creatinine clearance. Restricting protein intake to less than 1–9 g protein/kg bodyweight/day further reduced retention of nitrogenous waste products as measured by serum urea nitrogen concentrations, but at the expense of adequate protein nutrition. Diets providing less than 1–9 g protein/kg bodyweight/day promoted protein malnutrition characterised by hypoproteinaemia and hypoalbuminaemia in both normal dogs and dogs with renal failure. Serum protein concentrations were similar in normal and renal failure dogs, suggesting that, under the conditions of this study, normal and renal failure dogs may have similar protein requirements. Progressive dietary protein/phosphate restriction improved but did not normalise phosphate balance in renal failure dogs.