The Effects of Excess Tryptophan and Excess Lysine on the Production of Rickets in the Rat

Rats receiving the U.S.P. rachitogenic diet 2, supplemented with 1% L-lysine monohydrochloride, exhibited an increased rate of growth for the first 10 days and decreased femur ash for the first 20 days of the experiment when compared to control animals receiving no supplement. After 30 days the per cent ash of the femurs of the lysine-fed and the control groups were the same. DL-tryptophan, added to the rachitogenic diet at a level of 1%, gave rise to a decreased rate of growth and an increased femur ash. The growth rate and femur ash of the group of rats receiving both supplements simultaneously did not differ significantly from those of the control animals.