The necessity of niacin in rats fed on a high protein diet.
It is known that niacin itself is not necessary in rats when tryptophan is given in adequate amounts, because rats can biosynthesize niacin from tryptophan. In our experiment, young rats were fed on a 20%, 40%, 60%, or 70% casein diet with or without niacin. The rats fed on the 20%, 40%, and 60% casein diets did not require niacin for growth, but the rats fed on the 70% casein diet needed it. This phenomenon was attributed to the supposition that liver aminocarboxymuconate-semialdehyde decarboxylase activities increased according with the dietary casein levels. The conversion ratio of tryptophan-niacin in rats fed on the 70% casein diet became extremely low, and then the rats needed niacin.
Kimura
Naoko
N
Laboratories of Food Science and Nutrition, Department of Life Style Studies, School of Human Cultures, The University of Shiga Prefecture, Shiga, Japan.
Fukuwatari
Tsutomu
T
Sasaki
Ryuzo
R
Shibata
Katsumi
K
D000818:Animals; D002364:Caseins / Q000008:administration & dosage / Q000494:pharmacology*; D004032:Diet; D004305:Dose-Response Relationship, Drug; D009525:Niacin / Q000502:physiology*; D009751:Nutritional Requirements; D051381:Rats; D025101:Vitamin B 6 / Q000502:physiology; D015430:Weight Gain
D002364:Caseins; D009525:Niacin; D025101:Vitamin B 6