The formation of uric acid in birds

Abstract

and Queen's College, Belfast.) MUCH controv,ersy has arisen within recent years as to the nature of the forerunners of urea in mammals, axnd uric acid in birds. The work of the St Petersburg school on the urea production in mammials based especially upon the effects produced by the von Eck fistula in dogs has met with trenchant criticism by numerous workers, especiallv Munzer and Winterberg(l), Biedl and Winterberg 2), v. Karltreu (8), Filippi (4) and others. Although there is this diversity of opinion with rega.rd to the synthetic mode of origin of urea from ammonium salts in mammals, the work of Minkowski (6) on the allied subject, the synthetic origin of uric acid from ammonium salts in birds, has in the main withstood criticismn. Minkowski's work was so thorouglh that it might seem unnecessary to take up the suibject again, however for many reasons it was deemed advisable to try if possible to furnish more evidence either for or against the synthetic nmode of origin of uric acid in the bird's liver, and also to discover whether the purini source was of any importance in the bird's economy. One reason for re-opening the subject was that the operation employed by Minkowski of complete removal of the liver was of such a severe character and the birds lived for so short a time after the operation that it was difficult to draw conclusions as to the specific function of the liver from them. Then again in order to collect the urine free from faeces, the rectum was tied above the cloaca and this militated against the accuracy of the observations. Also the analytical methods employed were, although regarded as the most accurate at the time, in some cases fallacious.In order to remove some of these objections, attempts were made to affect the formation of uric acid in birds by less severe methods than the removal of the liver in its entirety. Thus in the first place experimnents were performed on ducks and geese with the view of

Role of Acid-Base Balance in the Physiology of Egg Shell Formation

“…In the same manner, in a resting hen, the elimination of uric acid is twice as important as in a laying hen (MONGIN, unpublished). Those variations seem to be linked with the acidosis, as MILROY (1904) showed, and, in fact, we have observed that in a hen forming a shell-less egg, the excretion of uric acid is of the same value as that of a resting hen.…”

“…Two results support this idea. MILROY (1904) showed that in acidosis, the excretion of uric acid decreases, and we note that, on the laying day of the first egg, the excretion of uric acid decreases while that of phosphates increases (MONGIN and LACASSAGNE, 1967). In the same manner, in a resting hen, the elimination of uric acid is twice as important as in a laying hen (MONGIN, unpublished).…”

Transcriptomic analysis of genes in the nitrogen recycling pathway of meat‐type chickens divergently selected for feed efficiency

“…Dietary protein is metabolized to provide amino acids for growth and various physiological processes in the body. The byproduct of amino acid catabolism is ammonia, which is toxic and, in avian species, eliminated as uric acid (Milroy ). Ammonia also is produced endogenously mainly in skeletal muscles, kidney and the brain (Spanaki & Plaitakis ), and efficient detoxification of ammonia requires coordinated effort between tissues to maintain ammonia homeostasis.…”

Proportions of Ammonia, Urea, Urate and Total Nitrogen in Avian Urine and Quantitative Methods for Their Analysis on a Single Urine Sample

“…material in the urine to be UA (Gibbs, 1929a, b) while many others used colorimetric methods to determine UA concentrations (Milroy, 1904;Mayrs, 1924;Davis, 1927;Shannon, 1938, Hart andEssex, 1942;Levine et al, 1947;Edwards and Wilson, 1954). These colorimetric methods have been criticized for sometimes giving unpredictable color development and because other purines, besides UA, may contribute to color development (Folin, 1934).…”