URINARY-EXCRETION OF ENDOGENOUS NITROGEN METABOLITES IN ADULT DOMESTIC CATS USING A PROTEIN-FREE DIET AND THE REGRESSION TECHNIQUE

The study was designed to determine urinary excretions of endogenous t otal, urea, ammonia and creatinine nitrogen in adult domestic cats, En dogenous urinary nitrogen metabolite excretions were determined by fee ding adult cats a protein-free diet for 10 d or by regression to zero protein intake of the urinary nitrogen metabolite excretions of adult cats fed four levels of dietary protein. The mean (+/- SEM) endogenous total, urea and ammonia nitrogen excretions for the cats fed the prot ein-free diet were 360 (+/- 11.3), 243 (+/- 8.8) and 27.6 (+/- 1.06) m g.kg body weight(-0.75) d(-1), respectively. Estimates of 316 (+/- 53. 9), 232 (+/- 43.4) and 33.7 (+/- 5.68) mg.kg body weight(-0.75).d(-1), respectively, were obtained using the regression technique. The diffe rences in results between the two techniques were not statistically si gnificant, Daily excretions of creatinine nitrogen were not significan tly (P = 0.64) different between the protein-free and regression techn ique (mean +/- SEM, 14.4 + 0.49 and 15.9 +/- 1.05 mg/kg body weight(0. 75), respectively). The endogenous urinary total and urea nitrogen exc retion of adult domestic cats is higher than values for other mammals such as humans, dogs, rats and pigs.