Inorganic or organic zinc and MUC-2, IgA, IL-17, TGF-[beta]4 gene expression and sIgA secretion in broiler chickens

The study compared the effect of dietary supplementation with an inorganic or organic source of zinc (Zn) on mucin 2 (MUC-2) and IgA gene expression, the cytokines IL-17 and TGF-[beta]4 and the secretory IgA content (sIgA) in broiler jejunum. One-day-old chickens were fed an unsupplemented basal diet (BD) or the same BD supplemented with 30 or 70 mg/kg of added Zn from ZnSO4·H2O or Zn chelate of glycine hydrate for 40 days. The highly expressed MUC-2 and IgA genes were observed in both groups supplemented with the low-dose Zn sources (30 mg/kg). A higher sIgA concentration was observed in both the ZnSO4 groups and the glycine-zinc/30 mg group. Our data indicate that the organic Zn chelate has better availability than the inorganic Zn source, and the low-dose Zn diets proved to be more beneficial to the maintenance of intestinal immune homeostasis.