title: Phenylalanine requirement of kittens and the sparing effect of tyrosine.
abstract: Two experiments were conducted to determine the phenylalanine requirement of the kitten and the ability of tyrosine to substitute for phenylalanine in the diet. In both studies purified L-amino acid diets were presented to six male and six female specific-pathogen--free kittens for six experimental periods of 10 d each, according to a 6 X 6 latin square design. In the first experiment, kittens were given tyrosine-free diets with either 4.0, 6.5, 7.5, 8.5, 9.5 or 15.0 g phenylalanine/kg diet. Mean daily weight gain and N retention were maximal at 7.5 g phenylalanine/kg diet. In the second experiment, diets contained 10.0 g tyrosine/kg diet, plus 1.5, 2.5, 3.5, 4.5, 5.5 or 10.0 g phenylalanine/kg diet. Mean daily weight gain and N retention were maximal at 3.5 g phenylalanine/kg diet. This indicates that the dietary phenylalanine requirement of the kitten is 7.5 g phenylalanine/kg diet, and that about half of this requirement may be replaced by tyrosine.
mesh_terms: D000818:Animals; D001835:Body Weight; D002415:Cats / Q000254:growth & development*; D004044:Dietary Proteins / Q000008:administration & dosage*; D004435:Eating; D005260:Female; D008297:Male; D009584:Nitrogen / Q000378:metabolism; D009751:Nutritional Requirements; D010649:Phenylalanine / Q000008:administration & dosage / Q000502:physiology*; D014443:Tyrosine / Q000008:administration & dosage / Q000502:physiology*
chemical_list: D004044:Dietary Proteins; D014443:Tyrosine; D010649:Phenylalanine; D009584:Nitrogen