Effects of Antimicrobial Peptides on Serum Biochemical Indices,Intestinal Mucosa Morphology and the Relative Expression Level of Tight Junction Protein Gene of Jejunum of Piglets

This study investigated the effects of dietary antimicrobial peptides( AMPs) on serum biochemical indices,intestinal mucosa morphology and the relative expression level of tight junction protein gene of jejunum in piglets. One hundred and eight 35-day-old piglets with similar average body weight( about 13 kg) were randomly divided into three groups with three replicates per group and twelve piglets per replicate. The piglets in three groups were fed a basal diet( control group),basal diet + 40 mg / kg bacitracin zinc + 20 mg / kg colistin sulfate( antibiotic group) and basal diet+300 mg / kg antimicrobial peptides( AMPs group),respectively. The pre-test period lasted 7 days,and test period lasted for 49 days. The results showed as follows: 1) compared with the control group,dietary AMPs could significantly improve the content of total protein and the activity of alanine transaminase( ALT) in serum of piglets( P0. 05); the content of serum total protein in AMPs group was significantly higher than that in the antibiotic group( P 0. 01). 2) Compared with the control group,AMPs could improve the villus height of duodenum,jejunum and ileum to some extent,but there was no significant difference( P0. 05); the crypt depth of jejunum in AMPs group was significantly lower than that in the control group( P0. 05); the villus height / crypt depth of duodenum in AMPs group and antibiotic group was significantly higher than that in the control group( P0. 05). 3) The relative expression level of Claudin-1 gene in AMPs group was significantly higher than that in the control group( P0. 05),and the relative expression level of Occludin and zonula occluden-1( ZO-1) genes were improved by 34. 83 % and 8. 57 % in jejunum of piglets( P0. 05),respectively; compared with the antibiotic group,the relative expression level of Claudin-1 gene was improved by 32. 52 %,but the relative expression level of ZO-1 gene was decreased by5. 00 % in AMPs group( P0. 05). In conclusion,diet supplementation of 300 mg / kg antimicrobial peptides can significantly improve the content of total protein and the activity of ALT in serum of piglets,effectively improve the intestinal mucosa morphology,and increase the relative expression level of tight junction protein gene of jejunum in piglets under the condition of this test.