关键词: 色氨酸, 蛋种鸭, 抗氧化性能

Abstract: This study aimed to determine the effect of dietary tryptophan（Trp）levels on antioxidant ability and Trp requirement for laying duck breeders. A total of 504 Longyan breeding ducks（body weight：1.20 ± 0.02 kg）aged 22 weeks were randomly allocated to 6 treatments，each with 6 replicates of 14 ducks. During the following 16 weeks，birds of differenttreatments were fed the basal diet with total Trp contents of 1.00，2.00，3.00，4.00，5.00 and 6.00 g/kg，respectively. The results showed that the dietary Trp level of 2 g/kg could result in the highest T?SOD activity in plasma（P<0.05），and the plasma serotonin content increased linearly and quadratically with dietary Trp supplemental levels（P<0.05）. The content of T?SOD and T?AOC in liver increased linearly and quadratically，and hepatic MDA content was lowest with dietary Trp level being 2 g/kg（P<0.05）. The gene expression of hepatic GPx1，SOD and Nrf2 increased linearly and quadratically， and the highest values was with Trp level of 4，2 and 1 g/kg，respectively（P<0.05）. The content of T?SOD and T?AOC in jejunum increased linearly and quadratically，and jejunal MDA content was lowest with the dietary Trp level of 3 g/kg（P< 0.05）. The gene expression of jejunal HO?1 and Nrf2 increased linearly and quadratically（P<0.05）. Collectively，dietary Trp level of 2 to 3 g/kg could improve the antioxidant ability in plasma，liver and jejunum in laying breeding ducks.

Key words: Tryptophan, Laying breeding duck, Antioxidant ability