1. U-C-14-lysine was administered by tube into the crop to turkey poul
ts fed on assay diets (maize + sesame + maize gluten meal) containing
varying concentrations of lysine, and partition of the label into body
components, carbon dioxide, and excreta was measured. 2. Deposition o
f C-14 label into breast and heart muscles responded positively to die
tary lysine concentration. There was no apparent relationship between
dietary lysine intake and deposition of label into carbon dioxide or e
xcreta. 3. Efficiency of lysine retention? above maintenance, was esti
mated to be 0.523 +/- 0.034. 4. Turkeys exhibited variable metabolic e
fficiency in the use of lysine as indicated by loss of U-C-14-lysine l
abel to expired carbon dioxide and to excreta by individual turkeys.