Developmental gene expression of antimicrobial peptide PR-39 and effect of zinc oxide on gene regulation of PR-39 in piglets

Two experiments were conducted to evaluate developmental gene expression of antimicrobial peptide PR-39 and effect of zinc oxide on gene regulation of PR-39 in piglets using semi-quantitative RT-PCR analysis. In experiment 1, fifteen female Tai-Hu pigs (a local breed in China) in five groups, each of three pigs at 1, 14, 28, 42 and 56 days of age were used to determine effect of age and weaning on mRNA expression of PR-39. In experiment 2, nine groups of pigs (total seventy-two female 36 days-age weaning Tai-Hu piglets) were assigned to three treatments (ZnO0, ZnO100 and ZnO3,000). The feeding experimental period lasted 15 days. After feeding experiment, nine pigs with three animals in each treatment were chosen to determine the effect of ZnO on PR-39 mRNA expression of pigs. The results showed that PR-39 mRNA levels increased steadily in postnatal day 1-28 (preweaning), and weaning significantly decreased PR-39 mRNA expression of piglets (p<0.05). ZnO3,000 (3,000 mg zinc/kg diet) significantly increased PR-39 mRNA expression (p<0.05) when piglets were feed ZnO3,000 diet for 15 days. ZnO100 (100 mg zinc/kg diet) also increased PR-39 gene expression, but the result was not statistically significant (p>0.05). The result was in accordance with the effect of ZnO3,000 and ZnO100 on weight gain of piglets and prevention of diarrhea.