Bioactivity of selenium-enriched exopolysaccharides produced by Enterobacter cloacae Z0206 in broilers

To investigate effects of Se-enriched exopolysaccharides (Se-ECZ-EPS) produced by Enterobacter cloacae Z0206 on growth performance, antioxidant status and immune function, 240 broilers were randomly assigned into five groups: the control group was fed a basal diet supplemented with 0.15 mg/kg Se (Na2SeO3), and the other four groups were fed with diets supplemented with Se-ECZ-EPS at 280, 560, 840 and 1120 mg/kg, respectively. Administration of Se-ECZ-EPS (840 and 1120 mg/kg) significantly increased average daily gain, decreased feed/gain ratio and enhanced antioxidant enzyme activities. Serum cytokine concentrations showed positive responses in birds treated with 560 and 1120 mg/kg Se-ECZ-EPS. Serum antibody titers against Newcastle disease virus in birds treated with 840 mg/kg Se-ECZ-EPS were significantly increased. These results suggested that Se-ECZ-EPS could enhance antioxidant status and immune function, and could be developed to a potentiator of the immune response in broilers, with the 840 mg/kg addition level being the most effective.