Hydrothermal synthesis of a new porous zinc oxide and its antimicrobial evaluation in weanling piglets

Porous zinc oxide has good application prospects as one of the new antibiotic alternatives. Research on its synthesis and antimicrobial evaluation has attracted more and more attentions in recent years. In our study, a new kind of porous zinc oxide was synthesized by a hydrothermal method using beta-cyclodextrin as organic small molecular template. Characterization of structure and morphology showed that the new porous zinc oxide was naturally agglomerated and exhibited microsphere morphologies with diameters of 1-2 mu m, which were assembled from two-dimensional nanosheets. Furthermore, the antimicrobial activity of porous zinc oxide was evaluated in vitro and in vivo. For Escherichia coli and Staphylococcus aureus inhibition experiments, the antimicrobial effect of porous zinc oxide was similar with nano zinc oxide at the same concentration. Additionally, the weanling piglets experiment lasted for 14 days to evaluate growth performance and diarrhea rate. Results showed that feed conversion ratio was improved significantly in 1,000 mg/kg porous zinc oxide group and 400 mg/kg chlortetracycline group compared with 3,000 mg/kg ordinary-size zinc oxide and 500 mg/kg porous zinc oxide treatments in the whole experiment period (P<0.05). Diarrhea rates in the 1,000 mg/kg porous zinc oxide group and 400 mg/kg chlortetracycline group were also substantially lower than those of 3,000 mg/kg ordinary-size zinc oxide and 500 mg/kg porous zinc oxide treatments (P<0.05). In conclusion, the new porous zinc oxide has a typical agglomerated and porous structure, and has superior antimicrobial activity versus ordinary-size zinc oxide. These novel findings provide solid data to support the application of porous zinc oxide in piglet husbandry.