中文摘要：

本试验研究蛋鸡日粮中添加不同水平壳聚糖对蛋品质及蛋黄抗氧化指标的影响，旨在为壳聚糖在蛋鸡日粮中的科学应用提供理论依据。试验根据体重和产蛋率相近的原则，选取26周龄健康无病的海兰褐壳蛋鸡450只，随机分为5个日粮处理组，每个处理6个重复，每个重复15只。对照组饲喂基础日粮，试验组分别在基础日粮中添加250、500、1000、2000mg／kg的壳聚糖。预试期7d，正试期8周。结果表明：在8周时，随着壳聚糖添加剂量的升高，蛋白高度呈显著的二次曲线升高效应（P〈0．05），而哈夫单位呈现极显著的二次曲线升高效应（P〈0．01）；随着蛋鸡日粮中壳聚糖添加水平的升高，壳聚糖组蛋黄中总超氧化物歧化酶（T—SOD）活性在4周和8周时均呈现显著的一次线性或二次曲线升高效应（P〈0．05）；此外，在试验8周时，壳聚糖组蛋黄中丙二醛（MDA）含量均低于对照组，并呈现显著的一次线性降低趋势（P=O．054），以添加500mg／kg壳聚糖组蛋黄fl-MDA含量最低。由此可见，日粮中适宜剂量的壳聚糖可在一定程度上改善蛋鸡的蛋品质和蛋黄的抗氧化功能。

英文摘要：

The present experiment was conducted to study the effects of ditferent levels ol ch]tosan m met on egg qum~ty and yolk antioxidative indexes of laying hens, to provide a theoretical basis for chitosan application in poultry diets. According to the principles of similar body weight and laying rate, 450 healthy 26-week-old Hy-line brown hens were selected and randomly divided into 5 dietary treatment groups, each with 6 replicates in which 15 hens were included. The control group was fed with the basal diet, and the diets of test groups were added with, respectively, 250, 500, 1000, 2000 mg/kg chitosan on the basis of control diet. The experimental period contained a pre-trial period of 7 days and a test period of 8 weeks which was divided into 2 periods equally, each lasting 4 weeks. The results showed that, with increasing levels of chitosan, egg white height showed a significant quadratic increase effects （P〈0.05） and Haugh units showed a highly significant quadratic increase effects （P〈0.001） at wk 8; T-SOD activity in yolk showed a significant linear or quadratic increase effects at wk 4 and 8 （P〈0.05）; in addition, MDA levels in yolk of chitosan groups were lower than those of the control group and 500 mg/kg chitosan group had the lowest level of MDA, and a significant linear decrease trend was showed at wk 8 （P=0.054）. It was concluded that appropriate dose of chitosan in diets could improve the egg quality and yolk antioxidative function to some extent.