本试验旨在研究饲粮蛋氨酸水平对30~38周龄临武鸭生产性能、蛋品质和血清生化指标的影响,以确定临武鸭产蛋高峰期蛋氨酸的需要量。选取体重相近、健康状况良好的临武鸭200羽,随机分为5组,每组5个重复,每个重复8只鸭。饲粮蛋氨酸水平分别为0.27%、0.32%、0.37%、0.42%、0.47%,试验全期63 d。结果显示:1)饲粮蛋氨酸水平对产蛋率和合格蛋率无显著影响(P>0.05)。0.37%、0.42%、0.47%组的平均日采食量和料蛋比均显著低于0.27%组(P<0.05),而0.37%组的平均蛋重和日产蛋量显著高于0.27%组(P<0.05)。0.37%组获得了除合格蛋率外最佳的产蛋性能。2)饲粮蛋氨酸水平对蛋鸭蛋形指数、蛋壳厚度、蛋黄色泽、蛋黄比例、蛋壳比例、蛋白比例的影响均不显著(P>0.05),但0.42%组蛋白高度和哈氏单位最大且显著高于0.27%和0.32%组(P<0.05)。3)饲粮蛋氨酸水平对蛋鸭血清中总蛋白、白蛋白、尿素氮、尿酸和丙二醛含量均无显著影响(P>0.05)。与0.27%组相比,其他4组的血清超氧化物歧化酶活性显著提高(P<0.05),0.37%、0.42%、0.47%组血清谷胱甘肽(GSH)含量和谷胱甘肽过氧化物酶(GSH-Px)活性均显著高于0.27%组(P<0.05)。4)以作为评价蛋氨酸需要量敏感指标的料蛋比和血清中GSH含量为依据,通过回归分析估测得到产蛋高峰期临武鸭获得最小料蛋比和最大GSH含量所对应的饲粮中蛋氨酸需要量分别为0.41%和0.43%。综上所述,在本试验条件下,当蛋氨酸水平为0.41%~0.43%时,产蛋高峰期临武鸭可获得最佳产蛋性能、蛋品质和血清生化指标。因此30~38周龄临武鸭蛋氨酸推荐量为0.41%~0.43%。

This experiment was conducted to study the effects of dietary methionine (Met) level on growth performance, egg quality and serum biochemical indices of Linwu ducks aged form 30 to 38 weeks, and to evaluate Met requirement of Linwu ducks during the peak laying period. A total of 200 healthy Linwu ducks with nearly same body weight were randomly assigned to 5 groups with 5 replicates in each group and 8 ducks in each replicate. Ducks in the 5 groups were fed basal diets supplemented with 0.27%, 0.32%, 0.37%, 0.42% and 0.47% Met, respectively. The experiment lasted for 63 days. The results showed as follows: 1) dietary Met level had no significant effects on laying rate and qualified rate of egg (P>0.05). The average daily feed intake and feed/egg in 0.37%, 0.42% and 0.47% Met group were significantly lower than that in 0.27% Met group (P<0.05), but the daily egg yield and average egg weight in 0.37% Met group was significantly higher than that in 0.27% Met group (P<0.05).The 0.37% Met group obtained the best performance except qualified rate of egg. 2) Dietary Met level had no significant effects on egg-shaped index, egg shell thickness, egg yolk color, yolk ratio, percentage of eggshell and protein ratio (P>0.05), but albumen height and Haugh unit in 0.42% Met group were highest and significantly higher than those in 0.27% and 0.32% Met group (P<0.05). 3) Dietary Met level had no significant effects on the contents of total protein, albumin, urea nitrogen, uric acid and malondialdehyde in serum (P>0.05). Compared with 0.27% Met group, the serum superoxide dismutase content in the other four groups were significantly improved (P<0.05). The serum glutathione (GSH) and glutathione peroxides content in 0.37%, 0.42% and 0.47% Met groups were significantly higher than that in 0.27% Met group (P<0.05). 4) There was a quadratic behavior for feed/egg and the content of GSH in serum according to the Met levels in the diets, with the requirements for those parameters established at 0.41% and 0.43%, respectively. In conclusion, dietary 0.41% to 0.43% Met level of Linwu ducks during the peak laying period can obtain the best performance, egg quality and serum biochemical indices. The Met recommended of Linwu ducks aged form 30 to 38 weeks is 0.41% to 0.43%.