URINARY AND PLASMA PURINE DERIVATIVES IN FED AND FASTED LLAMAS (LAMA-GLAMA AND LAMA-GUANACOE)

The changes in urinary and plasma purine derivatives in response to fa sting and level of feeding in Ilamas were examined. In one experiment, four Ilamas were gradually deprived of feed within 3 days and then fa sted for 6 days. Daily urinary excretion of purine derivatives decreas ed with feed intake and leveled on the last 3 days of fasting at 177 /- 26 mu mol/kg W-0.75. Allantoin and uric acid comprised 71% and 15% of total purine derivatives, respectively, in both led and fasted stat es, but hypoxanthine plus xanthine increased from 9% to 36%. Plasma co ncentration of allantoin declined with feed intake reduction, but thos e of uric acid (217 mu mol/l) and hypoxanthine plus xanthine (27 mu mo l/l) remained relatively unchanged. Concentration of uric acid was hig her than that of allantoin, probably due to a high reabsorption of uri c acid in renal tubules, which was measured as over 90%. In a second e xperiment, the four Ilamas were fed at 860 and 1740 g dry matter/d in a crossover design. Urinary coral purine derivatives excretion respond ed to feed intake (10.4 vs 14.4 mmol/d), although the observed differe nces did not reach significance. Compared with some ruminant species, it appears that the Ilama resembles sheep regarding the magnitude of u rinary purine derivatives excretion but is unique-in maintaining a hig h concentration of uric acid in plasma, which could be part of the Ila ma's adaptation to their environment.