| Abstrakt: |
Amino acid imbalances were produced in chick diets by the addition of 4% of single amino acids to diets low and adequate in niacin and pyridoxine in which the protein was furnished by 18% crude casein, 5% gelatin, and 0.3% DL-methionine. When L-arginine HCl, L-leucine, glycine, DL-aspartic acid, L-glutamic acid, or a DL-threonine-DL-allothreonine mixture was added to a diet adequate in niacin and pyridoxine, the growth rate of the chicks was not depressed. Additions of L-proline or DL-alanine decreased the growth rate slightly. Additions of DL-valine, L-cystine, DL-isoleucine, L-tyrosine, L-histidine HCl, DL-phenylalanine, DL-tryptophan, L- or DL-lysine HCl, or DL-methionine markedly decreased the growth rate. All amino acids depressed growth when added to a niacin-low diet; only DL-threonine-DL-allothreonine caused a growth depression when added to a pyridoxine-low diet, and this could be overcome by the addition of pyridoxine. |
