Effects of Dietary Zinc Oxide Nanoparticles on Growth, Diarrhea, Mineral Deposition, Intestinal Morphology, and Barrier of Weaned Piglets

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.