Effect of Astragalus and Astragalus polysaccharide on antimicrobial peptides PR-39 and protegrin-1 gene expression in pigs

This experiment was conducted to study the effects of micron Astragalus, 80 mesh Astragalus and Astragalus polysaccharide (APS) on antimicrobial peptides PR-39 and protegrin-1 gene expression in pigs using semi-quantitative RT-PCR analysis. One hundred twenty 60-day-old Duroc x Landrace x Yorkshire piglets (21.88 +/- 1.26 kg of average initial body weight) were randomly allotted to 4 treatments. Each treatment had 3 replicates (i.e. pens) with 10 pigs per pen. The basal diets were supplemented with 0, 5 g kg(-1) APS, 5 g kg(-1) 80 mesh Astragalus, and 5 g kg(-1) micron Astragalus, respectively, and the feeding experiment lasted 30 days. After the feeding experiment, 12 pigs with 3 animals in each treatment were chosen to determine the effect of Astragalus or APS on PR-39 and protegrin-1 mRNA expression of pigs. The results showed that supplementation with 5 g kg(-1) micron Astragalus significantly (P < 0.05) enhanced antimicrobial peptides PR-39 and protegrin-1 gene expression. Pigs fed the diet containing 5 g kg(-1) 80 mesh Astragalus also had higher PR-39 and protegrin-1 gene expression level than did the control (P < 0.05). However, micron Astragalus was more effective than 80 mesh Astragalus in enhancing PR-39 and protegrin-1 gene expression. Supplementation with 5 g kg(-1) APS reduced PR-39 and protegrin-1 gene expression (P < 0.05).