中文摘要：

研究旨在探讨壳聚糖对断奶仔猪免疫器官和肠道发育的影响，为断奶仔猪日粮中添加壳聚糖提供理论依据、选择28日龄断奶、体重为（11．56±1．61）kg、体型外貌接近、健康无病的180头杜×大×长三元杂交断奶仔猪随机分为5个日粮处理组，每个处理6个重复，每个重复6头猪。5种日粮分别是在基础日粮中添加0、100、500、1000和2000mg／kg的壳聚糖配制而成。试验期为28d，分前、后两期，每期14d。结果表明，日粮中添加壳聚糖对断奶仔猪免疫器官指数没有显著影响。随着壳聚糖添加量的增加，在14d时，空肠的体重校正长度呈现显著的二次曲线升高趋势（P=0．016）。28d时，十二指肠相对重量和体重校正长度均呈现一定的二次曲线升高趋势（P=0．063，P=0．064）。结果提示，饲料中添加壳聚糖可在一定程度上增加断奶仔猪十二指肠的相对重量和体重校正长度以及空肠的体重校正长度，对断奶仔猪的肠道发育，特别是小肠的发育有一定的促进作用。

英文摘要：

The present study aimed to explore lhe effects of chitosan on the development of ira-mune organs and gastrointestinal tracts in weaned piglets, and to provide a theoretical basis for adding chitosan in diets of weaning piglets. A total of 180 weaned piglets [Duroc× Yorkshire × Landrace,initial BW was （11.56±1.61） kg] were randomly divided into 5 treatments, each treat-ment consisted of 6 replicates with 6 piglets. The five treatments were led the basal diet supple-mented with 0, 100, 500, 1 000 and 2 000 mg/kg chitosan, respectively. The experiment lasted for 28 days and was divided into two periods. The results showed that： addition of chitosan hasno significant effect on the index of immune organs in weaned piglets. With the increasing of chitosan, the relative weight of juejunum showed an increased quadratically （P=0.016）： in addi-tion. On 28 d, the relative weight and length of duodenum showed a quadratic increasing trend（P=0.063, P=0.064）. The resuhs suggested that dietary chitosan increased the relative weightand length of duodenum, also increased the length of jejunum in weaned piglets to a certain ex-tent, and played a certain role in promoting development of intestinal tracts in weaned piglets.