本试验旨在研究添加和停用恩拉霉素对断奶仔猪生长性能，以及消化酶活性、肠道形态、肠黏膜钠/葡萄糖共转运载体1（SGLT 1）和二肽转运载体1（PepT 1）mRNA表达量的影响。选取21日龄断奶，体重相近，性别一致的PIC仔猪共20头，随机分成4个处理，每个处理5个重复，每重复1头猪。对照、处理1、处理2和处理3的日粮中分别添加0、5、20和80 mg/kg恩拉霉素，饲喂4周。第5周各处理仔猪停用恩拉霉素，饲喂基础日粮。第36天清晨，所有仔猪腹腔注射200 mg/kg脂多糖（LPS），注射后第3天屠宰取样测定消化酶活性、肠道形态、SGLT 1mRNA和PepT 1 mRNA表达量。结果表明，前4周，处理1和处理2的仔猪日增重与对照组相比有升高的趋势（P>0.05），处理3的仔猪日增重显著低于处理1和处理2（P<0.05）；第5周各处理日增重和采食量均无显著差异（P>0.05）。仔猪日粮中连续4周添加恩拉霉素、停用1周后，显著降低了各处理空肠淀粉酶、脂肪酶和胰蛋白酶的活性（P<0.05）；显著降低了十二指肠绒毛高度和绒毛高度/隐窝深度比（P<0.05）；并显著升高了SGLT 1、PepT 1 mRNA的表达量（P<0.05）。本试验表明，日粮中添加5～20 mg/kg的恩拉霉素对仔猪具有一定的促生长作用；停用恩拉霉素并受到应激的条件下会降低断奶仔猪消化酶活性，损坏肠黏膜结构，降低仔猪消化吸收功能。

This experiment was conducted to study the effects of supplementing and withdrawing enramycin on growth performance, activity of digestive enzyme, intestinal morphology and expression of sodium-glucose transporter 1 (SGLT 1) mRNA and peptide transporter 1 (PepT 1) mRNA in weanling piglets. Twenty PIC weanling piglets at 21-old-day with similar weight and gender were randomly allocated to 4 dietary treatments with 5 replicates in each treatment of 1 piglet of per replicate. The piglets were fed a basal diet supplemented with enramycin at 0, 5, 20, and 80 mg/kg for 4 weeks, respectively. At the 5th week, enramycin was withdrawed and all piglets in 4 treatments were received basal diet for 1 week. In the morning on day 36, all piglets were given intraperitoneal injection of LPS at 200 mg/kg body weight, and after 3 days of injection, piglets were slaughtered to determine activities of digestive enzyme, intestinal morphology and expression of sodium-glucose SGLT 1 mRNA and PepT 1 mRNA. Results showed that during the first 4 weeks, ADG in treatment 1 and treatment 2 tended to be improved, and ADG in treatment 3 significantly lower than that in treatment 1 and treatment 2 (P<0.05). But at 5th week, ADG and ADFI in all treatments were no significant difference (P>0.05). With supplemented with enramycin for 4 weeks then withdrawed for 1 week in diet of piglets, the activities of lipase, amylase and trypsin in jejunum were significantly depressed (P<0.05), and the ratio of the villus height to the crypt depth of duodenum were significantly increased (P<0.05), and expression of SGLT 1 mRNA and PepT1 mRNA was also significantly increased (P<0.05). In conclusion, supplementation with enramycin of 5～20 mg/kg in diet could improve growth of piglets; withdrawing enramycin could decrease activities of digestive enzyme, and damage structure of intestinal mucosa, and depress the function of digestion and resorption in piglets.［Chinese Journal of Animal Nutrition, 2010，22（1）:139-144］