Nitrogenous Metabolites in the Plasma of Chicks Adapted to High Protein Diets

SEVERAL investigators have reported levels of uric acid in the range of 4–6 mg./100 ml. in plasma of chicks (Bolton, 1947; Hsu and Combs, 1952; Krakoff and Karnofsky, 1958; Bell et al., 1959). Uric acid concentrations in plasma are influenced by age, sex, reproductive state and nutritional status. Stoewsand and Scott (1960) observed blood uric acid levels of chicks fed diets containing 84% isolated soybean protein to be approximately 16 mg./100 ml. Bell et al. (1959) reported that blood levels of urea remained relatively constant and were unaffected by sex, reproductive state or nutritional status of the chick. Ammonia is normally present in very low concentrations in chicken blood. Krakoff and Karnofsky (1958) observed a level of 2.2 μg./ml. of blood. Numerous studies have shown that the concentrations of plasma free amino acids in chickens are influenced both by the quantity and quality of protein consumed by the chick.…