Plasma urea, creatinine and uric acid concentrations in response to dehydration in racing pigeons (Columba Livia Domestica)

Plasma urea, creatinine and uric acid concentrations were determined in six racing pigeons that had been deprived of water for 3 days. Plasma urea concentration showed a 6.5- to 15.3-fold increase, creatinine a 1.2- to 1.5-fold increase and uric acid a 1.4- to 2-fold increase when compared with values before water deprivation. Although these increases were significant, plasma urea and plasma creatinine were the only variables that were significantly elevated above reference values for these variables. The findings show that, contrary to common belief, plasma urea (and less clearly plasma creatinine) concentration is a useful variable for detecting prerenal renal failure in birds, while plasma uric acid concentration, partly because of its wide reference range, is not useful for this purpose. The urea/creatinine ratio and the urea/uric acid ratio were significantly elevated when compared to pre-dehydration values and might prove to be useful parameters in clinical practice to differentiate between the various causes of renal failure in avian patients. The different renal excretory mechanisms of the various nitrogenous waste products offer an explanation for the findings in this study.