College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China; Hunan Engineering and Research Center of Animal and Poultry Science, Key Laboratory for Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, the Chinese Academy of Sciences, Hunan, CN 410125, China.
Int Immunopharmacol. 2013 Nov;17(3):670-6. doi: 10.1016/j.intimp.2013.07.023. Epub 2013 Sep 3.
This study was conducted to investigate how chitosan (COS) affects intestinal mucosal barrier function and to further explain mechanisms of COS on growth performance. Thirty piglets, weaned at 21 days of age, were challenged with enterotoxigenic Escherichia coli during preliminary trial period. Three groups of Piglets in individual pens were fed a corn-soybean meal diet containing no addition, 50 mg/kg chlortetracycline, or 300 mg/kg COS for 21 days. Jejunal morphology and histology were analyzed under light microscope. The concentrations of occludin proteins were determined by western blot. Immunohistochemistry assays were used to determine secretory immunoglobulin (sIgA) level. Real-time PCR was used to detect Toll-like receptor 4 (TLR4) and Claudin-1 in jejunal mucosa. Feeding COS or chlortetracycline reduced (P<0.05) feed conversion ratio. Villus length, villus length/crypt depth, and goblet cells, were increased (P<0.05), but villus width and crypt depth were decreased (P<0.05) in both COS and chlortetracycline groups. Intraepithelial lymphocytes were higher (P<0.05) in the COS group than both chlortetracycline and control groups. Occludin protein expression was increased (P<0.01) in the COS group, but was decreased (P<0.05) in the chlortetracycline group. Expression of sIgA protein was higher (P<0.05) in the COS group than both control and chlortetracycline groups, however TLR4 mRNA expression was decreased (P<0.05) in both COS and chlortetracycline groups. There was no difference in expression of claudin-1 among the three groups. In conclusion, chitosan and the antibiotic have similar effects in promoting piglet growth and reducing intestinal inflammation, but different effects on intestinal mucosal barrier function. This indicates that chitosan can replace chlortetracycline as a feed additive for piglets.
本研究旨在探讨壳聚糖（COS）如何影响肠道黏膜屏障功能，并进一步解释 COS 对生长性能的作用机制。在初步试验期间，将 21 日龄断奶仔猪进行肠产毒素大肠杆菌攻毒。三组仔猪分别在单个围栏中用含有不添加物、50mg/kg 金霉素或 300mg/kg COS 的玉米-豆粕日粮喂养 21 天。在光学显微镜下分析空肠形态和组织学。通过 Western blot 测定闭合蛋白的浓度。免疫组织化学检测法测定分泌型免疫球蛋白（sIgA）水平。实时 PCR 检测空肠黏膜中的 Toll 样受体 4（TLR4）和 Claudin-1。饲喂 COS 或金霉素降低（P<0.05）饲料转化率。绒毛长度、绒毛长度/隐窝深度和杯状细胞增加（P<0.05），但绒毛宽度和隐窝深度在 COS 和金霉素组均降低（P<0.05）。COS 组的上皮内淋巴细胞高于（P<0.05）金霉素和对照组。COS 组的闭合蛋白表达增加（P<0.01），但金霉素组降低（P<0.05）。COS 组的 sIgA 蛋白表达高于（P<0.05）对照组和金霉素组，而 TLR4mRNA 表达在 COS 和金霉素组均降低（P<0.05）。三组 Claudin-1 表达无差异。综上所述，壳聚糖和抗生素具有相似的促进仔猪生长和减轻肠道炎症的作用，但对肠道黏膜屏障功能的影响不同。这表明壳聚糖可以替代金霉素作为仔猪的饲料添加剂。
