PARTITION OF NITROGENOUS SUBSTANCES IN THE URINE OF SHEEP ON DIFFERENT DIETARY-PROTEIN INTAKES

The distribution of nitrogenous substances in urine was studied in she ep fed high (28.71 g N daily) and low (9.32 g N daily) protein diets f or 6-8 weeks. The concentrations of total nitrogen and urea, allantoin , free amino acids, uric acid, hippuric acid, creatinine, creatine and ammonia were measured in urine. The nitrogen content of these measure d substances was calculated. The results showed that the concentration s of total urinary nitrogen and nitrogen of individual nitrogenous sub stances were lower in sheep on a low protein diet, except for uric aci d nitrogen which was unchanged. Urea nitrogen was responsible for up t o 74% of the total urinary nitrogen of both groups of animals without any significant difference. The individual nitrogen portions of nitrog enous substances other than urea in total urinary-N did not exceed 7% during the intake of both diets. The intake of a low protein diet resu lted in a significant increase in the proportion of nitrogen from uric acid, hippuric acid, creatinine and free amino acids, while the fract ion of ammonia nitrogen in the total urinary N was significantly reduc ed. It is concluded that different protein or nitrogen intake in the d iet do not have any significant effect on the urea nitrogen fraction i n the total urinary nitrogen of sheep.