本试验旨在研究杜仲叶提取物对产蛋后期蛋鸡生产性能、蛋品质、蛋黄胆固醇含量及血清抗氧化指标的影响。采用单因素试验设计，选择产蛋率和体重相近、健康状态良好的420日龄海兰褐蛋鸡1 200只，随机分为4组，每组6个重复，每个重复50只。对照组饲喂基础饲粮，试验组分别在基础饲粮中添加100、200和300 g/t杜仲叶提取物。预试期1周，正试期8周。结果表明：1）与对照组相比，试验组的破软蛋率和死淘率均显著降低（P<0.05）。2）与对照组相比，试验第56天，试验组的蛋壳厚度、蛋壳强度均显著增加（P<0.05），蛋黄胆固醇含量极显著减少（P<0.01）。3）与对照组相比，试验组的血清超氧化物歧化酶和过氧化氢酶活性极显著升高（P<0.01），血清丙二醛含量极显著降低（P<0.01）。综上，饲粮中添加杜仲叶提取物可降低产蛋后期蛋鸡死淘率和破软蛋率，增加蛋壳厚度、蛋壳强度，降低蛋黄胆固醇含量，改善机体抗氧化能力，其中300 g/t杜仲叶提取物效果最好。

This experiment was conducted to investigate the effect of Eucommia leaves extract on performance, egg quality, yolk cholesterol content and serum antioxidant indexes of laying hens during late period of laying. Based on a single factor experiment design, a total of 1 200 laying hens (420-day-old) with similar laying rate and body weight were randomly divided into 4 groups with 6 replications per group and 50 hens per replicate. Laying hens in the control group were fed a basal diet, and the others in the experimental groups were fed the basal diets supplemented with 100, 200 and 300 g/t Eucommia leaves extract, respectively. The adaptation period lasted for 1 week and the formal period lasted for 8 weeks. The results showed as follows:1) compared with the control group, the unqualified egg rate and mortality rate of experimental groups were significantly decreased (P<0.05). 2) Compared with the control group, at the 56^th day, the eggshell thickness, eggshell strength of experimental groups were significantly increased (P<0.05), the yolk cholesterol content of experimental groups was significantly decreased (P<0.01). 3) Compared with the control group, the activities of superoxide dismutase and catalase in serum of experimental groups were significantly increased (P<0.01), while the serum malondialdehyde content of experimental groups was significantly decreased (P<0.01). In conclusion, dietary supplemented with Eucommia leaves extract can reduce the unqualified egg rate and mortality rate, increase the eggshell thickness and eggshell strength, reduce the yolk cholesterol content, improve the body antioxidant capacity. The best sepplemented level of Eucommia leaves extract in the basal diet was 300 g/t.