Urinary excretion of purine derivatives and prediction of rumen microbial outflow in goats

The present study examined the relationship between duodenal flow of purine bases and urinary excretion of their derivatives (i.e., Allantoin, uric acid, xanthine and hypoxanthine) in selected milk goats. Three adult Granadina goats fitted with a T-shaped cannula in the abomasum. were used to determine the endogenous contribution to renal excretion of purine derivatives and urinary recovery of abomasaly infused purine bases as yeast-RNA. Animals were fed alfalfa at maintenance level. The endogenous contribution of purine derivatives was determined at fasting (11.34 mg N/W-0.75 or 202.2 mumol/W-0.75) and it was similar to that obtained in sheep but lower than that reported in cattle. Urinary PD excretion responded linearly to incremental supply of purine bases throughout the abomasal cannula, these recovery (%) averaged 76. Xanthine oxidase activities in goat tissues were, in plasma 0.001 (S.E. 0.0001) i.u./ml, in liver 0.12 (S.E. 0.021) i.u./g and in duodenum 0.0009 (S.E. 0.00026) i.u./g. Again, activities were lower than those detected in cows but close to values determined in sheep. A similar response model between both species (sheep and goat) is suggested. (C) 2002 Elsevier Science B.V. All rights reserved.