Quantitative efficacy of niacin sources for chicks: nicotinic acid, nicotinamide, NAD and tryptophan.
A niacin-deficient diet based upon corn and casein was used to establish growth-promoting efficacy of various sources of niacin activity. In the presence of excess dietary nicotinamide, chicks fed the corn-casein diet achieved maximal weight gain when 100 mg/kg of L-tryptophan was supplemented. The basal diet for efficacy studies therefore contained 100 mg/kg of added tryptophan and no supplemental nicotinic acid. Weight gain in the linear response surface of the growth curve proved to be a far better measure of niacin bioactivity than tissue accumulation of NAD(P). Slope-ratio growth efficacy studies indicated that excess dietary tryptophan was 1.94 +/- 0.14% as efficient as nicotinic acid in furnishing bioavailable niacin activity (52:1, wt:wt). Relative to nicotinic acid used as a standard (100%), nicotinamide bioactivity was 124%. Nicotinamide in NAD was utilized with an efficiency of 95% relative to nicotinamide per se.
Oduho
G W
GW
Department of Animal Sciences, University of Illinois at Urbana-Champaign 61801.
Baker
D H
DH
D000704:Analysis of Variance; D000821:Animal Feed; D000818:Animals; D001681:Biological Assay; D002645:Chickens / Q000254:growth & development*; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009132:Muscles / Q000187:drug effects / Q000378:metabolism; D009243:NAD / Q000008:administration & dosage / Q000494:pharmacology*; D009249:NADP / Q000096:biosynthesis; D009525:Niacin / Q000008:administration & dosage / Q000494:pharmacology*; D009536:Niacinamide / Q000008:administration & dosage / Q000494:pharmacology*; D012044:Regression Analysis; D014364:Tryptophan / Q000008:administration & dosage / Q000494:pharmacology*; D015430:Weight Gain / Q000187:drug effects
D009243:NAD; D009536:Niacinamide; D009525:Niacin; D009249:NADP; D014364:Tryptophan