土霉素和磺胺二甲嘧啶对堆肥过程中微生物群落多样性及抗性基因的影响

发布时间：2018-05-06 16:49

  本文选题：土霉素 + 磺胺二甲嘧啶　； 参考：《西北农林科技大学》2015年硕士论文

【摘要】：畜禽养殖业中,抗生素作为防治疾病药物被大量使用,但大部分抗生素会随畜禽粪便排出。好氧高温堆肥是畜禽粪便无害化处理和资源化利用的主要途径之一,而畜禽粪便中残留的抗生素会对好氧堆肥过程产生一定的影响。本试验选取畜禽粪便中残留浓度较大、检出率较高的土霉素(OTC)和磺胺二甲嘧啶(SM2)为研究对象,将添加不同浓度抗生素的畜禽粪便与小麦秸秆混合堆肥,采用酶活分析法、Biolog法、T-RFLP技术、高效液相色谱法及实时定量PCR技术等,研究了OTC和SM2对堆肥过程中堆料理化性质、酶活性、微生物群落多样性、抗生素残留及抗性基因的影响。主要结果如下:1.OTC和SM2对堆料理化性质及酶活性的影响经过35 d的堆肥处理,各处理堆体温度均在55℃以上保持了4 d,达到了无害化处理的标准。各处理GI指数均大于85%,C/N小于16,达到了腐熟标准,但添加抗生素会在短期内延缓堆肥进程。高浓度(140 mg·kg-1 OTC+30 mg·kg-1 SM2)抗生素对脱氢酶活性呈先抑制后促进的作用,而对脲酶活性的抑制作用则表现在堆肥后期。添加抗生素仅在堆肥前期对纤维素酶活有显著抑制作用。2.OTC和SM2对堆肥过程中微生物群落多样性的影响Biolog结果表明,在堆肥腐熟期高浓度处理AWCD值、Shannon指数和Simpson指数显著大于CK处理。主成分分析表明,抗生素改变了堆肥过程中微生物群落功能多样性,高浓度处理作用更为显著,起分异作用的碳源主要为糖类、羧酸类及氨基酸类。采用T-RFLP技术分析堆肥过程中细菌和真菌群落多样性,结果表明抗生素能改变堆肥过程中微生物群落多样性,且对真菌群落的影响更大。高浓度处理显著提高了细菌群落多样性而降低了真菌群落的多样性。聚类分析表明,添加抗生素使堆肥过程中细菌和真菌的群落结构发生了变化,在堆肥高温期,高浓度抗生素显著改变了真菌群落结构。3.堆肥中OTC和SM2的降解及抗性基因丰度的变化堆肥35 d后,低浓度(10 mg·kg-1 OTC+1 mg·kg-1 SM2)和高浓度(140 mg·kg-1 OTC+30 mg·kg-1 SM2)处理中OTC残留率分别为2.8%和4.2%,SM2含量均减少到检测限以下。抗生素在堆肥中的降解符合一级动力学方程,半衰期为0.56 d~1.24 d。从堆肥各时期样品中共检出5种四环素类抗性基因,2种磺胺类抗性基因,1种I类整合子,其中tet X基因丰度最大,而dfr A7最小。说明好氧高温堆肥是一种有效去除抗生素的方法,但不能彻底去除抗性基因,还需要进一步处理还降低抗性基因对环境带来的风险。
[Abstract]:In livestock farming, antibiotics are widely used as disease control drugs, but most antibiotics are excreted with animal feces. Aerobic high temperature composting is one of the main ways of harmless disposal and resource utilization of livestock and poultry feces, and the antibiotic residues in animal manure will have a certain effect on aerobic composting process. In this experiment, oxytetracycline (OTC) and sulfadimethazine (SM2), which had higher residual concentration and higher detection rate, were selected as the research objects. The mixed compost of livestock and poultry manure with different concentrations of antibiotics and wheat straw was used as the research object. The effects of OTC and SM2 on physical and chemical properties, enzyme activity, microbial community diversity, antibiotic residues and resistance genes during composting were studied by using Biolog T-RFLP, high performance liquid chromatography (HPLC) and real-time quantitative PCR. The main results were as follows: 1. The effects of OTC and SM2 on the physicochemical properties and enzyme activity of the stacks reached the standard of innocuous treatment after 35 days of composting. The temperature of each treatment remained above 55 鈩，

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