Effects of hydroxychloride and sulfate form of zinc and manganese supplementation on superoxide dismutase activity and immune responses post lipopolysaccharide challenge in poultry fed marginally lower doses of zinc and manganese

Abstract

Effects of hydroxychloride (OHCl) and sulfate form of zinc and manganese supplementation on immune responses of birds fed marginally lower levels of zinc and manganese during an experimental lipopolysaccharide (LPS) injection were studied. In experiment I, 30-week-old layer birds were fed 50mg/kg Zn+45mg/kg Mn or 100mg/kg Zn+90mg/kg Mn in sulfate or OHCl form and injected with 0 or 500μg/kg LPS in a 2 (50mg Zn+45mg Mn and 100mg Zn+90mg Mn) X 2 (sulfate and OHCl) X 2 (0 and 500μg LPS) factorial setup of treatments for 10 weeks. Among LPS-injected birds, those receiving 50mg ZnOHCl+45mg MnOHCl had comparable heterophil and monocyte superoxide dismutase (SOD) activity compared to the birds fed 100mg Zn+90mg Mn. Compared to the birds injected with PBS, LPS injection upregulated cathelicidin and IL-1 relative mRNA amounts in monocytes from birds fed 100mg Zn+90mg Mn, both in sulfate and OHCl form, and in birds fed 50mg ZnOHCl+45mg MnOHCl, but not in the birds fed 50mg ZnSO4+45mg MnSO4. In experiment II, one-day-old broiler birds were fed 50mg ZnOHCl+45mg MnOHCl, 50mg ZnOHCl+90mg MnOHCl, 100mg ZnOHCL+45mg MnOHCl, 100mg ZnOHCl+90mg MnOHCl, 50mg ZnSO4+45mg MnSO4, or 100mg ZnSO4+90mg MnSO4 for 21 and 42 days. Birds fed 100mg ZnOHCl+45mg MnOHCl form had a comparable heterophil and monocyte SOD activity and monocyte cathelicidin mRNA amounts compared to the group fed 100mg Zn+90mg Mn. Increasing the ZnOHCl content from 50mg to 100mg/kg Zn reversed (P >0.05) the decrease in SOD activity and monocyte cathelicidin mRNA levels of the 50mg ZnOHCl+45mg MnOHCL fed group, and increasing the MnOHCl content from 45mg to 90mg/kg in the 100mg ZnOHCl+45mg MnOHCl group further increased SOD activity. In conclusion, birds fed diets with lower amounts of zinc and manganese in sulfate form decreased SOD activity and IL-1 and cathelicidin amounts during inflammation, and either increasing the dietary zinc and manganese content or feeding zinc and manganese in OHCl form synergistically increased the SOD activity and IL-1 and cathelicidin mRNA amounts in immune cells.