This study was conducted to investigate effects of dietary zinc oxide nanoparticles (nano-ZnOs) on growth, diarrhea rate, mineral deposition (Zn, Fe, and Mn), intestinal morphology, and barrier of weaned piglets. A total of 384 weaned piglets (Duroc × Landrace × Yorkshire) in 4 groups were fed a basal diet supplemented with 0, 400, and 800 mg/kg nano-ZnOs or 3000 mg/kg ZnO for 14 days. Compared with the control group, 800 mg/kg nano-ZnOs and 3000 mg/kg ZnO significantly increased average daily gain and decreased diarrhea rate of weaned piglets. There was no significant difference among ZnO and nano-ZnO groups. ZnO and nano-ZnOs did not affect serum activities of glutamic oxalacetic transaminase, glutamic-pyruvic transaminase, and lactate dehydrogenase. However, ZnO and 800 mg/kg nano-ZnOs significantly increased zinc concentrations in plasma, liver, pancreas, and tibia, without affecting Fe and Mn concentrations. Compared with the control group, 800 mg/kg nano-ZnOs significantly reduced plasma diamine oxidase activity, decreased total aerobic bacterial population in mesenteric lymph node, enhanced mRNA expressions of occludin, ZO-1, IL-1β, IL-10, TNF-α, and ki67 in ileal mucosa, and increased villous height, width, crypt depth, and surface area. Compared to ZnO group, 800 mg/kg nano-ZnOs significantly decreased aerobic bacterial population, enhanced mRNA expressions of occludin, IL-1β, IL-10, and TNF-α, and reduced fecal zinc concentration. These results indicated that 800 mg/kg nano-ZnOs might be a potential substitute for 3000 mg/kg ZnO in diets of weaned piglets.
Keywords: Cytokine expression; Growth performance; Intestinal barrier; Weaned piglet; Zinc deposition; Zinc oxide nanoparticle.