高锌对早期断奶仔猪肠形态和肠屏障通透性的影响

Effect of high level of zinc oxide on intestinal morphology and permeability in early weanling piglets.

选取40头21日龄断奶仔猪研究高剂量氧化锌对早期断奶仔猪肠形态和肠屏障通透性的影响.断奶当天屠宰4头,其余36头仔猪按照体重相近、公母各半分为2组,每组3个重复,每个重复6头.对照组饲喂基础日粮,试验组饲喂基础日粮+3000mg·kg-1锌(氧化锌),每组随机选取仔猪屠宰和灌服检测溶液,并连续收集6h尿液,分别于21、24、28和35日龄取样观察肠形态学变化和检测血浆D-乳酸含量、二胺氧化酶(DAO)活性和尿中乳果糖/甘露醇比率.试验结果显示:仔猪早期断奶引起肠道形态的显著变化,28日龄时隐窝深度增加了13.93%(P<0.05)、绒毛高度/隐窝深度比下降了20.53%(P<0.05),差异均达到显著水平;24日龄时早期断奶仔猪血浆D-乳酸含量、DAO活性和尿中乳果糖/甘露醇比率升高到显著水平(P<0.05),且维持至35日龄.而日粮中添加高剂量锌可以有效地缓解早期断奶给仔猪肠道带来的应激反应;显著地降低断奶对肠通透性造成的影响,可以很好地抑制断奶仔猪血浆D-乳酸含量、DAO活性和尿中乳果糖/甘露醇比率的升高,并使其维持在较低水平.说明高剂量氧化锌可以缓解断奶引起的肠形态和肠通透性改变,维持肠屏障的正常功能.

A total of 40 piglets weaned at 21 d of age were used to study the effects of high level of zinc oxide on intestinal morphology and permeability in early weanling piglets. Four piglets were randomly selected and killed before weaning, and the rest were randomly divided into two groups of three replicates each （six piglets per replicate） on the basis of initial body weight and sex, which were fed basal diet （control） and basal diet＋3000 mg· kg^-1 Zn （as ZnO）. Piglets were selected randomly to slaughter and oral administration of mixture with lactulose and mannitol, then their urine was collected after six hours. The changes of intestinal morphology were determined at d 21, 24, 28 and 35 of age. At the same time, plasma D-lactate level, diamine oxidase （DAO） activity and urine lactulose to mannitol ratio were measured to evaluate the intestinal permeability. The results show that the intestinal lesion of piglets was obvious in early weanling piglets, with crypt depth increasing by 13, 93% （P〈0.05） and villus height/ crypt depth decreasing by 20.53%（P〈0. 05） at 28 d of age; plasma D-lactate level, DAO activity and urine lactulose to mannitol ratio increased significantly at 24 d of age, and remained high level to 35 d of age. However, supplementation with high level of zinc oxide alleviated stress and decreased intestinal permeability with reducing plasma D-lactate level, DAO activity and urine laetulose to mannitol ratio caused by early weanling of piglets. It is suggested that the addition of high level of zinc oxide relieved lesion of intestinal morphology and permeability of early weanling piglets so that to maintain the better intestinal barrier function.