title: Purine availability and metabolism in dogs fed single-cell protein or RNA.
abstract: For the evaluation of single-cell protein (SCP) the proportion of dietary purines made available by digestion and absorption was estimated with dogs (Dalmatian) in total urine collection experiments. The animals received a low purine control diet with 25% casein, diets with 25-100% replacement of casein by a bacterial SCP grown on methanol, and the control diet plus yeast RNA purine equivalent to SCP diet. Nucleic acids, bases, and purine metabolites were determined by reversed-phase high-pressure liquid chromatography. The quantitative influence of dietary purines (x) on renal purine excretion (y) was described by the equation (millimoles per day) y = 0.57x + 3.52 (r = 0.955) indicating the endogenous excretion rate of 3.5 mmol/day and the metabolic availability of 57% of ingested purines. As the ratio of urate to allantoin increased with purine intake, individual equations were established for both metabolites. On the control diet + RNA and SCP diet (100% replacement for casein), purine intakes of 20.0 and 18.2 mmol/day resulted in purine excretion values of 7.3 and 11.4 mmol/day (P less than 0.05). The proportion of free bases in the latter diet appeared as the main reason for this differences. Other influences are discussed.
mesh_terms: D000481:Allantoin / Q000652:urine; D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism*; D002364:Caseins / Q000378:metabolism*; D004044:Dietary Proteins / Q000378:metabolism*; D004285:Dogs; D005260:Female; D008297:Male; D009696:Nucleic Acids / Q000008:administration & dosage; D009753:Nutritive Value; D011687:Purines / Q000378:metabolism*; D012331:RNA, Fungal / Q000378:metabolism*; D012441:Saccharomyces cerevisiae; D014527:Uric Acid / Q000652:urine
chemical_list: D001426:Bacterial Proteins; D002364:Caseins; D004044:Dietary Proteins; D009696:Nucleic Acids; D011687:Purines; D012331:RNA, Fungal; D014527:Uric Acid; D000481:Allantoin