Influence of Antibiotics and Tryptophan Deficiency on Growth in the Rat

Abstract
The antibiotics, terramycin, achromycin and erythromycin, when added at a level of 0.01% of the diet, were able to improve the growth of male rats fed a 9% casein diet. When tryptophan was supplied in addition to antibiotics, no further improvement was obtained. The same antibiotics were less effective in female rats.