Cecal degradation of uric acid in Gambel quail

Abstract

In birds, urine enters the lower gastrointestinal tract from paired ureters and can be moved in a retrograde fashion into the colon and digestive ceca. As a major constituent of urine, uric acid is carried into these regions of the gastrointestinal tract. In these locations the chemical composition of the urine, including uric acid, could be altered. To examine this possibility the postrenal degradation of uric acid in the hindgut (ceca, colon, and ileum) of the Gambel quail (Callipepla gambelii) was investigated in vitro to determine the location of activity and the possible source of uricolytic enzymes. Significant breakdown of uric acid was observed in all cecal preparations; only minor amounts were degraded in the ileum and colon. The cecal degradation amounted to 15-49% of the uric acid estimated to be produced by the quail. Attempts to demonstrate uric acid decomposition by bacteria cultured from ceca gave inconclusive results.