Effect Of Dietary Supplementation And Withdrawal Of Enramycin On Growth Performance And Digestive Physiological Function Of Piglets

The antibiotic growth promoter have been used in animal production for nearly 60 years. Enramycin is a kind of polypeptide antibiotic,has the strong inhibitory action to the gram-positive bacteria.It is not easily absorbed by organism,not residued in animal,and not have the drug resistance.In overseas it is widely used as antibiotic growth promoter.It is sure that the antibiotic can enhance organism nutrient digestion,and the absorption function.What is the impact of antibiotics on intestinal physiology especially after withdrawal remains to be further studied.This experiment was conducted to study the effect of supplementing and withdrawing enramycin on digestive enzyme,intestinal morphology and SGLT 1,PepT 1 mRNA expression of piglets.Twenty PIC piglets weaned at 21days were randomly allocated to four dietary treatments with 5 replicates in each treatment.The piglets were fed a basal diet supplemented with enramycin at 0,5,20,and 80 mg/kg for 4 weeks.At the end of the 4 weeks,enramycin was withdrawed and all treatments received basal diet for 1 week.After that,all pigs were given intraperitoneal injection of LPS at 200 mg/kg bodyweight.3 days after injection,pigs were slaughtered.Results shown that supplementation of 5 mg/kg and 20 mg/kg enramycin tended to improve average daily gain(ADG),but ADG of pigs fed with 80 mg/kg enramycin decreased significantly compared to control group(P＜0.05).In the fifth week,each treatment ADG ADFI and F/G were not significant different.This experiment significantly depresses the activity of digestive enzyme in jejunum.And the ratio of the villus height to the crypt depth of small intestine significantly increased.It also significantly increase the expression of SGLT1,PepT1 mRNA.The present study indicates that withdrawing antibiotic can depress the function of digestion and resorption of piglets.