Ethanol and leucine as possible stress factors in rats marginally deficient in niacin and vitamin B-6.

Young rats were fed a purified diet containing no niacin (and 0.85 g/kg tryptophan) and only 0.5 mg/kg vitamin B-6. Three supplements were tested in a 2 x 2 x 2 multifactorial experiment: 1) 25 mg/kg niacin plus 7.3 mg/kg vitamin B-6; 2) 15 g/kg L-leucine; and 3) 12.15% (wt/wt) ethanol in the drinking water. The ethanol, for those receiving it, contributed approximately 15% of the rats' total energy intake, and their diets had some of the carbohydrate omitted to maintain approximately the same proportion of energy to other nutrients. The vitamin supplements stimulated 4-wk weight gain (and gain-feed ratio), but ethanol depressed it, and to a significantly greater extent in the absence of the vitamin supplement. Excretion of N1-methylnicotinamide was increased only by the vitamin supplement. Leucine had no significant effects either by itself or by interaction with the other supplements.