Dietary protein effects on urinary nitrogen components of the hen

IT HAD been shown that dietary energy level had an effect on hen's urinary nitrogen components (Richardson et al., 1968). It was of interest to study possible effects of dietary protein on certain nitrogenous components of the urine, i.e. uric acid, ammonia, urea, creatine and amino acid nitrogen. Folin's laws (Folin, 1905) of human urine composition were based on such a study. Rather than switch from a high-protein to a non-protein diet as Folin, it was decided to conduct a protein depletion type study. It was reasoned that by following the daily urinary nitrogen components, these might indicate the protein level necessary for maintenance. It was hypothesized that as long as the nitrogen requirement was met or exceeded, the urinary nitrogen excretion would depend on the intake, but when the maintenance requirement was not met, the hen would mobilize body stores and the relative amounts of urinary nitrogen components would . . .