Protein quality of dietary yeast rna studied in growing rats 2. influence of rna intake on nitrogen balance and urinary compounds
Greife, H.A.; Molnar, S.; Nofer, E.
Archiv fuer Tierernaehrung 31(11-12): 753-762
In a balance trial with growing rats, the influence of dietary RNA on N metabolism was tested. Yeast RNA was supplied at 4 levels ranging from 7.8-31.2% of diets N (1.64% in DM (dry matter) from casein + DL-methionine). The mean apparent digestibility of the RNA-N ingested was determined as 95%. Of the RNA-N consumed, 16.6% were retained, as measured by N-balance technique, whereas no retention of the RNA-N was observed by body-N analysis. This discrepancy in RNA-N retention was attributed to the relatively increased N-losses with higher N-intake when using the N-balance method. By regression analysis it was found that 80.2% of the RNA-N consumed were excreted via kidneys. Of the RNA-N intake, 45.5% appeared in urea, 30.9% in allantion, and only 1.1% and 0.3% in uric acid and creatinine, respectively.