Utilisation of U-14C-lysine by young turkeys

1. U-14C-lysine was administered by tube into the crop to turkey poults 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 of 14C label into breast and heart muscles responded positively to dietary lysine concentration. There was no apparent relationship between dietary lysine intake and deposition of label into carbon dioxide or excreta. 3. Efficiency of lysine retention, above maintenance, was estimated to be 0.523 +/- 0.034. 4. Turkeys exhibited variable metabolic efficiency in the use of lysine as indicated by loss of U-14C-lysine label to expired carbon dioxide and to excreta by individual turkeys.