本试验旨在研究纳米硒对产蛋鸡生产性能、血清免疫和生化指标及蛋黄中硒含量的影响。选取324只29周龄体重相近的健康产蛋鸡，随机分为6个组，每组6个重复，每个重复9只鸡。对照组（A组）饲喂基础饲粮，试验组（B、C、D、E、F组）分别饲喂在基础饲粮中添加0.1、0.2、0.3、0.4、0.5 mg/kg纳米硒的饲粮。预试期为7 d，正试期为63 d。结果表明：1）与对照组相比，第21天C组的料蛋比显著降低（P<0.05），第42、63天B、D组的破壳率显著降低（P<0.05）。各组产蛋率、平均蛋重均无显著差异（P>0.05）。2）与对照组相比，第42天，E组血清免疫球蛋白M（IgM）、免疫球蛋白A（IgA）含量显著提高（P<0.05）；各组血清免疫球蛋白G（IgG）含量差异不显著（P>0.05）；第63天，各组血清IgM、IgA、IgG含量均差异不显著（P>0.05）。3）与对照组相比，第42天，D组血清白蛋白（ALB）含量显著提高（P<0.05），D组血清甘油三酯（TG）和葡萄糖（Glu）含量极显著降低（P<0.01），F组血清总蛋白（TP）含量显著升高（P<0.05），E、F组血清尿酸（UA）含量显著降低（P<0.05）；第63天，F组血清TP含量显著提高（P<0.05），F组血清碱性磷酸酶（ALP）活性和Glu含量显著降低（P<0.05）。4）与对照组相比，第21天，C、D、E、F组蛋黄硒含量显著或极显著提高（P < 0.05或P < 0.01）；第42天，试验组蛋黄硒含量均显著或极显著提高（P < 0.05或P < 0.01）；第63天，C、D、E、F组蛋黄硒含量极显著提高（P<0.01）。各试验期蛋黄硒含量均以F组最高，且第42天各试验组蛋黄硒含量均高于第21、63天。与对照组相比，除第42天试验组蛋黄锌含量显著高于对照组（P<0.05）外，各组各试验期蛋黄铁、锰、锌、铜含量均无显著差异（P>0.05）。由此可见，饲粮添加纳米硒能改善产蛋鸡的生产性能，提高血清免疫力，促进机体蛋白质的合成，降低血液胆固醇含量，促进机体健康，提高蛋黄中硒含量。综合考虑，以饲粮添加0.4 mg/kg纳米硒饲喂42 d作用效果较明显。

This experiment was conducted to study the effects of nano-selenium on performance, serum immune and biochemical indices and yolk selenium content of laying hens. A total of 324 laying hens (29 weeks of age) were randomly allotted to 6 groups with 6 replicates in each group, and each replicate contained 9 hens. Hens in the control group (group A) were fed a basal diet, and hens in experimental groups (groups B, C, D, E and F) were fed the diets supplemented with 0.1, 0.2, 0.3, 0.4 and 0.5 mg/kg nano-selenium, respectively. The adjustment period lasted for 7 days, and the experimental period lasted for 63 days. The results showed as follows:1) compared with the control group, the feed to egg ratio at the 21st day of group C was significantly decreased (P<0.05), the grain-hulling rate at the 42nd and 63rd day of groups B and D was significantly decreased (P<0.05). There were no significant effects on laying rate and average egg weight among all groups (P>0.05). 2) Compared with the control group, the contents of immunoglobulin M (IgM) and immunoglobulin A (IgA) in serum at the 42nd day of group E were significantly increased (P<0.05), and there was no significant effect on serum immunoglobulin G (IgG) content at the 42nd day among all groups (P>0.05). There were no significant effects on serum IgM, IgA and IgG contents at the 63rd day among all groups (P>0.05). 3) Compared with the control group, at the 42nd day, the serum albumin content of group D was significantly increased (P<0.05), the serum triglyceride (TG) and glucose (Glu) contents of group D were significantly decreased (P<0.01), the serum total protein (TP) content of group F was significantly increased (P<0.05), the serum uric acid (UA) content of groups E and F was significantly decreased (P<0.05). Compared with the control group, at the 63rd day, the serum TP content of group F was significantly increased (P<0.05), the serum alkaline phosphatase (ALP) activity and Glu content of group F were significantly decreased (P<0.05). 4) Compared with the control group, the yolk selenium content at the 21st day of groups C, D, E and F was significantly increased (P < 0.05 or P < 0.01), the yolk selenium content at the 42nd days of experimental groups was significantly increased (P < 0.05 or P < 0.01), the yolk selenium content at the 63rd day of groups C, D, E and F was significantly increased (P<0.01). The yolk selenium content of group F was the highest at all experiment period, and the yolk selenium content of experimental groups at the 42nd days was higher than that at the 21st and 63rd day. There were no significant effects on yolk iron, manganese, zinc and copper contents among all groups (P>0.05), except the yolk zinc content at the 42nd day of experimental groups was significantly higher than that of control group (P<0.05). In conclusion, dietary nano-selenium can improve the performance of laying hens, improve the serum immunity, promote the synthesis of proteins of organism, reduce the content of cholesterol in blood, promote the health of hens and increase the yolk selenium content. Comprehensive consideration, the optimum level of nano-selenium in the diet is 0.4 mg/kg, and the effect is more obvious when experiment last for 42 days.