Abstract
Nitrogen utilization (N retention/N intake), excretion of nitrogenous compounds and blood urea concentration were compared between adult cockerels fed on a 5% protein diet and a 5% protein diet plus urea. The intake of protein nitrogen and urea nitrogen was 280mg each per kg body weight per day.
Feeding of urea did not affect total introgen excretion, and in consequence significantly increased nitrogen utilization to about 3 times (P<0.01).
Excretion of uric acid and urea was not changed but excretory ammonia significantly increased by feeding of urea (P<0.05).
Blood urea concentration rose sharply up to the top level of about 35 mg per 100ml at 6hr after feeding of urea, then decreased rapidly to 9hr, thereafter gradually.
The results indirectly support that dietary urea is utilized possibly through nitrogen recycling system involving cecum when a low protein diet is fed to adult cockerels.
