本试验旨在研究冬季饲粮维生素A水平对蛋鸡生产性能和蛋品质的影响。选取525只的健康海蓝褐蛋鸡，随机分为5个处理，每个处理5个重复，每个重复21只鸡。对照组饲喂基础饲粮（维生素A水平为8 000 IU/kg）；试验组饲粮维生素A水平分别为10 500、13 000、15 500和18 000 IU/kg，其他维生素水平与对照组一致。试验期42 d。结果显示：1）与对照组相比，试验组蛋鸡的产蛋量和产蛋率显著提高（P<0.05），料蛋比显著降低（P<0.05），并且随着饲粮维生素A水平的增加，3个指标均呈二次函数规律变化（P<0.05）；但饲粮维生素A水平对蛋鸡采食量、蛋重和破蛋率无显著影响（P>0.05）。2）随着饲粮维生素A水平的增加，蛋壳硬度呈线性和二次函数规律变化（P<0.05），蛋壳比重呈二次函数规律变化（P<0.05）；但饲粮维生素A水平对蛋形指数、蛋壳厚度、蛋白高度、蛋黄颜色、哈氏单位、蛋黄比重无显著影响（P>0.05）。3）饲粮维生素A水平对鸡蛋成分无显著影响（P>0.05）。由此可见，冬季饲粮维生素A水平为10 500~15 500 IU/kg时可以获得较好的生产性能和蛋品质。

This experiment was conducted to study the effects of dietary vitamin A level on performance and egg quality of laying hens in winter. A total of 525 healthy Hy-line laying hens were randomly divided into 5 treatments with 5 replicates per treatment and 21 hens per replicate. Hens in the control group were fed a basal diet (contained 8 000 IU/kg vitamin A), and the others in experimental groups were fed diets which contained 10 500, 13 000, 15 500 and 18 000 IU/kg vitamin A, respectively. All groups had the same level of other vitamins. The experiment lasted for 42 days. The results showed as follows: 1) compared with the control group, the egg production and laying rate in experimental groups were significantly increased (P<0.05), but the ratio of feed to egg (F/G) was significantly decreased (P<0.05). The egg production, laying rate and F/G showed a quadratic equation change with dietary vitamin A level increasing (P<0.05). Dietary vitamin A level had no significant effects on feed intake, egg weight and the rate of broken eggs (P>0.05). 2) With dietary vitamin A level increasing, the eggshell hardness showed linear and quadratic equation changes (P<0.05), and the eggshell proportion showed a quadratic equation change (P<0.05). Dietary vitamin A level had no significant effects on egg shape index, eggshell thickness, albumen height, yolk color, Haugh unit and yolk proportion (P>0.05). 3) Dietary vitamin A level had no significant effect on component of eggs (P>0.05). In conclusion, dietary vitamin A level from to 10 500 to 15 500 IU/kg can obtain the best performance and egg quality of laying hens in winter.