Effect of dietary zinc on morphological characteristics and apoptosis related gene expression in the small intestine of Bama miniature pigs.

To investigate the effects of dietary zinc (Zn) on small intestinal mucosal epithelium, 6-month-old male Bama miniature pigs were randomly allocated into three groups and treated with three levels of Zn (Control, T1, and T2 diet supplemented with 0, 50, and 1500mg/kg Zn, respectively, as zinc sulfate) for 38days. The samples of small intestine tissues, serum, and feces were collected. The results showed that Zn concentrations of small intestine in the T2 group were higher than those in the control and T1 groups (p<0.05). In the T2 group, the pharmacological dose of dietary Zn treatment caused marked damage to the small intestinal epithelium. The expression of Bax, cleaved caspase-3, and caspase-8 were increased in the duodenum and the jejunum of the T2 group (p<0.05). The mRNA transcript levels of BAX, CYCS and CASP3 genes were upregulated in the duodenum and the jejunum of the T2 group. We concluded that a diet with a pharmacological dose of Zn increased the accumulation of Zn and the expression of Bax, cleaved caspase-3, and caspase-8, which might activate the apoptosis and lead to the marked injury of porcine small intestinal epithelium.