Abstract: Two factorial experiments were carried out to evaluate the effects of dietary protein level, on yields of feed intake, body weight, the nitrogen retention rate and body measurements of Gaoyou ducks at 28 and 140 days of age. Two diets similar in their energy content and differing markedly in their protein content, in which the dietary protein were 14% and 16%, respectively, were feed to Gaoyou ducks in this experiment. Until at the 140 days of age, 8 ducks were choose from every treatment on the average weight of group to carry out metabolism experiment. The results showed that Gaoyou ducks were gain the better growth performance and the best nitrogen retention rate, when the dietary protein was 14% from 29 to 140 days of age.

Key words: Gaoyou duck; dietary protein level; growth performance; nitrogen retention rate