Methionine requirement of developing turkeys from 8-12 weeks of age

Two experiments were conducted with Large White male turkeys from 8-12 weeks of age to estimate the methionine requirement for optimum growth rate and feed efficiency. The first experiment was conducted with five pens of 22 turkeys per treatment when the mean minimum temperature was 17.2 C and the maximum 32.2 C. The second experiment was conducted with four groups of 14 turkeys per pen when the mean minimum temperature was 1.4 C and the maximum 12.4 C. Initial body weight and rate of gain in the first experiment was lower than that in Experiment 2. Maximum growth and feed efficiency in Experiment 1 were obtained with a methionine level between 1.32 and 1.41 g./mcal. of M.E. and in Experiment 2 between 1.27 and 1.43 g. Adding 0.1% l-cystine to the basal diet in Experiment 2 failed to improve growth or feed efficiency significantly. The estimated requirement for methionine in these experiments agrees with the present estimate of the National Research Council.