Abstract: [Objective]To assess the effects of dietary supplementation of high-efficient coated zinc oxide on growth performance, blood biochemical indexes and trace elements （copper, iron, zinc and manganese） excretion in weaned piglets. [Method]A total of 60 healthy Duroc-Landrace-Yorkshire ternary hybrid weaned piglets aged 28 days and averagely weighed （7.26±0.46） kg were selected and randomly assigned into an ordinary zinc oxide group fed with a basal diet adding 1 966 mg/kg ordinary zinc oxide （zinc content was 1 500 mg/kg）, a high-efficient coated zinc oxide group fed with a basal diet adding 1 000 mg/kg high-efficient coated zinc oxide （zinc content was 500 mg/kg）, and a control group fed with a basal diet without supplementation of zinc oxide in any forms. There were 10 replicates in each group and 2 piglets in each replicate. The experiment lasted for 35 days, including a 7-day pre-experiment period and a 28-day formal experiment period. At the end of the experiment, the average daily feed intake, average daily gain, feed/gain ratio （FGR） and diarrhea rate of the experimental piglets were calculated; the whole blood hemoglobin content, Cu, Zn-superoxide dismutase （Cu, Zn-SOD） activity, and blood contents of copper, iron and zinc were determined; the fecal contents of copper, iron, zinc and manganese were tested. [Result]Compared with control group, ordinary zinc oxide group and high-efficient coated zinc oxide group had significantly （P<0.05） increased average daily feed intake and average daily gain, and had significantly （P<0.05） decreased FGR and diarrhea rate; no significant （P>0.05） differences in average daily feed intake, average daily gain, FGR and diarrhea rate between high-efficient coated zinc oxide group and ordinary zinc oxide group were observed. There were no significant （P>0.05） differences in whole blood hemoglobin contents among the three groups; Cu, Zn-SOD activity in high-efficient coated zinc oxide group was significantly （P<0.05） higher than that in control group and ordinary zinc oxide group; no significant （P>0.05） differences in blood contents of copper and iron among the three groups were found; ordinary zinc oxide group had significantly （P<0.05） higher blood content of zinc compared with control group and high-efficient coated zinc oxide group. The coat index in high-efficient coated zinc oxide group was superior to that in ordinary zinc oxide group. The fecal content of zinc in high-efficient coated zinc oxide group was extremely significantly （P<0.01） lower than that in ordinary zinc oxide group; there were no significant （P>0.05） differences in fecal contents of copper, iron and manganese among the three groups. [Conclusion]Dietary supplementation of high-efficient coated zinc oxide containing 500 mg/kg zinc decreases the diarrhea rate and improves the growth performance, coat index and antioxidant ability of piglets. In addition, it reduces the fecal excretion of zinc, which is conductive to control the environmental pollution.

Key words: weaned piglets, high-efficient coated zinc oxide, growth performance