【作者】 王燕； 温馨； 陈桂秀； 吴银宝； 廖新俤；

【Author】 WANG Yan;WEN Xin;CHEN Gui-xiu;WU Yin-bao;LIAO Xin-di;College of Animal Science,South China Agricultural University;Key Laboratory of Tropical Agriculture Environment of Ministry of Agriculture,South China Agricultural University;

【机构】 华南农业大学动物科学学院； 华南农业大学农业部华南热带农业环境重点实验室；

【摘要】 兽用抗生素的土壤环境行为是当前研究的热点。国内外主要的研究方法有以下三种:(1)经体内代谢后含兽用抗生素猪粪+空白土壤(A组),(2)空白猪粪+兽用抗生素原形+空白土壤(B组),(3)兽用抗生素原形+空白土壤(C组)。本文以生产中常用的土霉素(Oxytetracycline,OTC)为研究对象,比较以上三种研究方法对土霉素在土壤中降解行为的影响。结果表明:(1)各试验组土霉素在土壤中的降解规律符合一级动力学方程,其降解率均达到98.36%以上。各试验组间土霉素在土壤中的降解半衰期有显著差异(P<0.05),A组<B组<C组;(2)含猪粪处理组(A、B组)土霉素降解速度快于C组,可能有如下两个原因:第一、猪粪的加入使土壤微生物量碳和氮、细菌数量和多样性增强而产生氨,导致试验前期pH上升,从而有利于土霉素的降解;第二、细菌、蜡样芽孢杆菌数量显著增加加速了土霉素在土壤中的降解;(3)A组降解速度显著快于B组的原因可能是由于反应过程A组代谢产物4-epi-OTC的浓度显著低于B组,加快了母本土霉素的转化。由于兽用抗生素是经体内代谢后随畜禽粪便等排泄物进入环境介质,因此在研究兽用抗生素在土壤中的降解行为时,采用体内代谢法能更好的反映其降解规律,获得更准确的研究成果。更多还原

【Abstract】 Currently,more and more research focused on the environmental behavior of veterinary antibiotics in soil.The commonly studied using the following methods of adding antibiotics to the soil:(i) adding manure collected from animals fed with a diet containing antibiotics,(ii) adding antibiotic-free animal manure spiked with antibiotics and(iii) directly adding antibiotics.Oxytetracycline(OTC) was used as a model antibiotic to compare the effect of the three commonly used antibiotic addition methods on OTC degradation behavior in soil.The results showed that(1) degradation rates of OTC in all treatments were above 98.36%and fit a first-order kinetic model.OTC degradation half-lives show the following significant differences(P <0.05):manure from swine fed OTC(treatment A) <antibiotic-free manure +OTC(treatment B) < OTC(treatment C);(2) the treatments presenting manure(A and B)can enhance enzyme activity,microbial biomass carbon and nitrogen,bacterial diversity index,thus increase the pH,or increase the quantity of Bacillus cereus to increase the degradation of OTC in the soil when it compared to the treatment C;(3) the difference between treatment A and B might be because of the concentrations of 4-epi-OTC.Low 4-epi-OTC content could also increase the degradation of OTC in the soil.Because the main entry route for veterinary antibiotics into soil is via the manure of animals given with antibiotics,the most appropriate method to study the degradation and ecotoxicity of antibiotic residues in soil may be to use manure from animals that are given a particular antibiotic,rather than by adding it directly to the soil.更多还原