日粮中添加及停用恩拉霉素对断奶仔猪生长性能和消化吸收功能的影响

Effects of Supplementing and Withdrawing Enramycin on Growth and Digestion Absorption Function of Weanling Piglets

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 sodiumglucose 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 5^th 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.