This experiment was conducted to investigate the effects of excess methionine on growth performance and blood parameters of Peking ducks during 7 to 28 days of age,and to determine the maximum safe level of methionine of Peking ducks during 7 to 28 days of age. A total of 252 seven-day-old healthy male Peking ducks were randomly allotted to 6 groups with 7 replicates per group and 6 ducks per replicate according to similar pen weight. The ducks in 6 groups were fed diets with methionine levels of 0. 48%,0. ...