Excretion of purine derivatives by ruminants: effect of exogenous nucleic acid supply on purine derivative excretion by sheep

Excretion of endogenous and exogenous purine derivatives in sheep: effect of increased concentrate intake.

The present study examined the endogenous urinary excretion of purine derivatives (PD; allantoin, uric acid and xanthine plus hypoxanthine) in fed animals. Four Rasa Aragonesa ewes fitted with simple cannulas in the rumen and proximal duodenum were used. Animals were given a lucerne (Medicago sativa) hay diet, as sole feed (A) or supplemented, respectively, with 220 (B), 400 (C), and 550 (D) g ...

Cviii. the Excretion of Purine

Endogenous purine and pyrimidine derivative excretion in pregnant sows.

The present experiment was carried out to study the endogenous losses of purine and pyrimidine derivatives from pregnant sows. Three pregnant and three non-pregnant Large White x Landrace sows were fed on a purine-free diet composed of starch, glucose, sucrose and vegetable oil, with casein as the protein source. The experiment began, for the six animals, after diagnosis of pregnancy and was di...

Excretion of purine derivatives by ruminants: recycling of allantoin into the rumen via saliva and its fate in the gut.

The saliva of sheep was shown to contain significant concentrations of uric acid (16(SD 4.5) mumol/l) and allantoin (120(SD 16.4) mumol/l), sufficient to recycle purine derivatives equivalent to about 0.10 of the normal urinary excretion. When allantoin was incubated in vitro in rumen fluid, it was degraded at a rate sufficient to ensure complete destruction of recycled allantoin. In a series o...

The Urinary Excretion of Purine Derivatives in Sheep Offered Nitrogen and Phosphorus Deficient Diets

Urinary allantoin excretion as a measure of microbial protein production, has been shown to be responsive to ruminal nitrogen (N) supply (Balcells et al. 1993). Dietary phosphorus (P) deficiency has also been observed to reduce microbial protein flow (Gunn and Ternouth 1994). The aim of this experiment was to examine the effects of P and N deficiencies upon microbial protein formation, as deter...