發(fā)布時(shí)間：2018-03-10 13:28

  本文選題：抗生素抗性基因　切入點(diǎn)：tet(C)　出處：《黑龍江八一農(nóng)墾大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著畜禽養(yǎng)殖業(yè)的快速發(fā)展,越來越多的抗生素類藥物以藥劑或飼料添加劑的形式被廣泛的應(yīng)用于畜禽養(yǎng)殖業(yè)中。這些抗生素并不能完全被畜禽吸收,絕大多數(shù)的抗生素類藥物會(huì)以母體化合物或者代謝物的形式隨著畜禽糞便排出體外,從而造成了抗生素在畜禽糞便中的積累,進(jìn)而誘導(dǎo)產(chǎn)生了大量的耐藥菌。這些耐藥菌含有的抗生素類抗性基因(Antibiotic Resistance Genes,ARGs)不僅可以在不同環(huán)境介質(zhì)中傳播擴(kuò)散,而且還能持久性殘留,比抗生素本身對環(huán)境的危害要大。堆肥是降解和消除ARGs的有效方法,但ARGs在堆肥過程中的變化分布卻不清楚。本研究通過牛糞和樹葉堆肥的方式,分析堆肥過程中土霉素(OTC)的含量及四環(huán)素類抗性基因tet(C)多樣性的變化規(guī)律,為闡明ARGs在堆肥過程中的消減機(jī)制提供數(shù)據(jù)支撐,也為減少抗生素的殘留及控制ARGs的傳播提供理論依據(jù)。本研究以牛糞和樹葉為主要堆肥原料,經(jīng)檢測牛糞中不含土霉素。試驗(yàn)設(shè)置兩個(gè)處理,即處理組(TG)和空白對照(CK)。其中TG的土霉素添加量為60 mg·kg-1,CK不添加土霉素。在堆肥的的0 d、7 d、14 d、28 d、63 d取樣并測其理化參數(shù)和土霉素的含量。結(jié)果顯示,TG的土霉素含量在第7 d下降到初始含量的一半為32 mg·kg-1,到堆肥結(jié)束,土霉素含量為2 mg·kg-1。TG和CK溫度50℃以上分別持續(xù)16 d和18 d,最高溫度分別為62.0℃和61.5℃。TG和CK的pH在整個(gè)堆肥過程中均保持在7.5以上。堆肥結(jié)束時(shí),兩處理含水率變化差異性顯著(p0.05),TG和CK的含水率由初始的70.0%分別下降到28.4%和34.8%。在整個(gè)堆肥過程中,TG和CK全碳含量逐漸降低,到堆肥結(jié)束,TG和CK全碳含量由初始的36.86%分別下降到26.34%和26.48%,差異性不顯著(p0.05)。TG和CK全氮含量均先升高后降低,然后逐漸升高,到堆肥結(jié)束,TG和CK全氮含量由初始的1.59%分別升高到1.86%和2.0%。通過分子克隆技術(shù)研究四環(huán)素類抗性菌的多樣性變化,結(jié)果表明,TG和CK兩種堆肥過程中,四環(huán)素類抗性菌的多樣性和種類均有差異。CK的微生物類群主要包括Uncultured bacterium、Salmonella enterica和Enterococcus faecalis,隨著堆肥的進(jìn)行CK處理四環(huán)素類抗性菌多樣性逐漸減少。從堆肥第14 d開始,CK的堆體中只能檢測到一種四環(huán)素類抗性菌。TG的微生物類群主要包括Uncultured bacterium、Salmonella enterica、Enterococcus faecalis、Uncultured Geobacter sp.和Lactococcus garvieae,在堆肥初期,TG的四環(huán)素類抗性菌的多樣性增加,但是到堆肥結(jié)束時(shí)僅檢測到Uncultured Geobacter sp。利用冗余分析(RDA)研究兩處理堆體中四環(huán)素類抗性菌的菌群結(jié)構(gòu)與環(huán)境因子的相關(guān)性。RDA二維排序圖顯示,TG和CK的四環(huán)素類抗性菌的菌群結(jié)構(gòu)差異性較大。相關(guān)分析未發(fā)現(xiàn)對四環(huán)素類抗性菌的菌群結(jié)構(gòu)變化具有顯著性影響的環(huán)境因子(p0.05)。通過SPSS16.0對土霉素含量與四環(huán)素類抗性菌的多樣性進(jìn)行顯著性分析可知,土霉素對四環(huán)素類抗性菌多樣性變化具有顯著性影響(p0.05)。
[Abstract]:With the rapid development of livestock and poultry breeding, more and more antibiotic drugs are widely used in animal husbandry in the form of medicament or feed additive. These antibiotics can not be completely absorbed by livestock and poultry. Most antibiotics are excreted in the form of parent compounds or metabolites, resulting in the accumulation of antibiotics in animal manure. In turn, a large number of drug-resistant bacteria were induced. The antibiotic resistance gene, Antibiotic Resistance Genes-ARGs, not only spread in different environmental media, but also persistent residues. Composting is an effective way to degrade and eliminate ARGs, but the distribution of ARGs in composting process is not clear. The content of oxytetracycline (OTC) and the diversity of tetracycline resistance gene (tetC3) during composting were analyzed, which provided data support for elucidating the mechanism of ARGs subtractive during composting. In this study, cattle dung and leaves were used as the main composting materials, the oxen manure was detected without oxytetracycline, and two treatments were set up in the experiment, which were used to reduce the residue of antibiotics and to control the spread of ARGs. TG) of the treatment group and CK of the blank control group, in which the amount of oxytetracycline was 60mg 路kg ~ (-1) CK without adding oxytetracycline. The physicochemical parameters and the content of oxytetracycline were measured at 0 d ~ 7 d ~ 14 d ~ (14) d ~ (28) d ~ (63) d of compost. The results showed that the content of oxytetracycline in TG was determined. On the 7th day, half of the initial content decreased to 32 mg 路kg ~ (-1), and the compost reached the end of the compost. The content of oxytetracycline was 2 mg 路kg-1.TG and CK temperature was above 50 鈩，

本文編號：1593543