Study on bacteriostatic activity of nanocerium dioxide against two aquatic pathogenic Vibrio spp.
Nanocerium dioxide(nCeO2)is an important new type of rare earth metal oxide with high oxidation resistance.In order to develop new antimicrobial agents witch are efficient,environmentally friendly and non-resistant,we obtained nCeO2 from cerium nitrate hexahydrate by high temperature calcination.We sudied the in vitro antibacterial activity of nCeO2 on two kinds of aquatic pathogens(Vibrio vulnificus and V.parahaemolyticus),and verified the antibacterial effect of nCeO2 by in vivo experiment of Macrobrachium rosenbergii.The results show that:1)The obtained nCeO2 was relatively pure.The particle dia-meter was 25.03 nm,the Zeta potential(mV)was-5.65,and the dispersion in the solution was relatively uniform.2)The mini-mum inhibitory concentrations(MIC)of nCeO2 against V.vulnificus and V.parahaemolyticus were 128 and 256 μg·mL-1,re-spectively,and the minimum bactericidal concentrations(MBC)all were 512 μg·mL-1.The diameter of the inhi-bition ring was 21.50 mm for V.vulnificus and 17.42 mm for V.parahaemolyticus.3)The three concentrations of nCeO2(1/2 MIC,1 MIC and 2 MIC)all significantly improved the extracellular AKP activity,relative conductivity of bacterial solution,nuc-leic acid content and soluble protein content in the extracellular(p＜0.05).4)The nCeO2 supplementation in the feed signifi-cantly reduced the mortality of M.rosenbrei in V.vulnificus and V.parahaemolyticus infection models(p＜0.05).The results in-dicate that nCeO2 has a good inhibitory effect on aquatic pathogens V.vulnificus and V.parahaemolyticus,and the antibacterial action may be related to its destruction of cell wall membrane integrity and cell membrane permeability.
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