[Digestive and metabolic utilization of dietary nitrogen in rats receiving tannic acid, sulfite and ethanol, administrated singly or in combination].

In a first experiment, 8 groups of male rats received for 6 months diets containing 23 p. 100 casein: 1) standard semi-synthetic diet (R); 2) standard diet with 1 p. 100 potassium metabisulfite (S); 3) standard diet with 3.2 p 100 tannic acid (T); 4) standard diet with sulfite and tannic acid (ST); 5) standard diet in which ethanol replaced 30 p. 100 of the carbon-hydrate energy (E); 6) standard diet with sulfite and ethanol (SE); 7) standard diet with tannic acid and ethanol (TE); 8) standard diet with sulfite, tannic acid and ethanol (STE). In another experiment, 6 groups of male rats received for 6 months diets containing 11.5 p. 100 casein: 1) standard diet (R) fed ad libitum; 2) standard diet (R') fed in restricted amounts equal to those ingested by the rats receiving the diet with tannic acid; 3) standard diet with tannic acid (T); 4) standard diet with sulfite and tannic acid (ST); 5) standard diet with tannic acid and ethanol (TE); 6) standard diet with sulfite, tannic acid and ethanol (STE). The digestive utilization of dry matter, digestive utilization and biological value of nitrogen were determined at the beginning of the experiments and after two and six months. 1. Tannic acid caused a marked decrease in food intake in animals fed 11.5 p. 100 casein but had only a slight effect in animals fed 23 p. 100 casein. 2. Fecal excretion of dry matter was strongly enhanced in rats fed tannic acid. Sulfite and ethanol had a slight effect when given singly, but caused modifications to the effect of tannic acid when they were associated with it. 3. Fecal excretion of nitrogen was strongly increased by tannic acid, and this effect was quantitatively modified by the presence of the two other compounds, particularly by sulfite. 4. Ethanol generally increased the urinary excretion of nitrogen but interactions between the effects of the three substances were observed. Particularly, the simultaneous feeding of the three substances provoked after 6 months a poor metabolic utilization of the nitrogen, and also a lower digestive utilization of the proteins. 5. Generally all the effects of the three compounds were more marked when the dietary level of protein was low than when it was high.