Effects of zinc oxide supported on zeolite on growth performance, intestinal microflora and permeability, and cytokines expression of weaned pigs

Effects of zinc oxide supported on zeolite (Z-ZnO) on growth performance, intestinal microflora and permeability, and cytokines expression of weaned pigs were investigated. A total of 210 piglets, with an average weight of 6.12 ± 0.22 kg weaned at 21 ± 1 d age, were randomly allotted to five groups for two weeks. The five treatments were the control (basal diet), and the basal diet supplemented with 300, 600 or 900 mg Zn/kg from Z-ZnO or 2250 mg Zn/kg from ZnO. The results showed that incremental levels of Z-ZnO increased average daily gain (linear P=0.001; quadratic P=0.004), daily feed intake (linear P=0.006; quadratic P=0.019) and jejunal transepithelial electrical resistance (linear P=0.007; quadratic P=0.021), and decreased the postweaning scour scores (linear P<0.001; quadratic P<0.001), mucosal-to-serosal flux of fluorescein isothiocyanate dextran 4 kDa (linear P<0.001; quadratic P<0.001), the viable counts of Clostridium and Escherichia coli in small intestinal contents (linear P<0.001; quadratic P<0.001). At 7 days after weaning, on d 7 postweaning, as Z-ZnO inclusion increased, the mRNA levels of TNF-α and IFN-γ in jejunal mucosa were decreased linearly (P<0.001 and P=0.001) and quadratically (P<0.001 and P=0.001), and those of TGF-β1 and IL-10 were increased linearly (P=0.002 and P=0.010) and quadratically (P=0.009 and P=0.028). Supplementation with 600 or 900 mg Zn/kg from Z-ZnO was as efficacious as 2250 mg Zn/kg from ZnO in enhancing growth performance, alleviating postweaning diarrhea, improving intestinal microflora and barrier function of weaned pigs. The results indicated that Z-ZnO could be used as a substitute for pharmacological addition of ZnO in weanling pigs.