Some factors affecting urinary and faecal nitrogen loss by chickens fed on a protein-free diet

1. In adult colostomised cockerels, the rates of urinary and faecal nitrogen loss were measured when feeding low- and high-energy, protein-free diets after a preliminary period during which diets of differing energy and protein contents had been fed. 2. Urinary nitrogen excretion increased with increasing protein and decreasing energy in the preliminary diet. 3. Urinary nitrogen excretion was high during the fist 3 d of feeding a high-energy, protein-free diet, decreased rapidly during the next 3 d and thereafter become relatively constant. However, in the case of a low-energy, protein-free diet, urinary nitrogen excretion gradually declined throughout the trial period of 15 d, resulting in increased urinary nitrogen excretion. 4. After a 3-d period of adjustment faecal nitrogen loss from birds fed on a protein-free diet was relatively constant under the conditions examined.