摘要

       现代养猪场通常饲养多种动物，并广泛依赖饲料添加剂（包括抗生素和重金属）来促进动物生长。尽管如此，作为环境中抗生素抗性基因 (ARGs) 的重要储存库，养猪场每种动物的 ARGs 排放尚未得到表征。本研究的目的是确定哪种动物类型对中国典型养猪场中 ARGs 排放到环境中的贡献最大。结果表明，金霉素（CTC）、铜和锌是典型的饲料添加剂，保育猪（NP）的饲料和猪粪中抗生素和重金属的浓度普遍高于其他动物类型，而妊娠母猪 (GS) 的 ARG 含量最高。与其他动物类型相比，GS 每头每天释放的抗生素、ARG 和移动遗传元件 (MGE) 最多。一个典型的养猪场以 10,000 头猪为原料，每天可释放约 4.0 ± 1.3 × 1017 个 ARGs 基因拷贝，而在育种率和粪便生产系数方面，生长和育肥猪 (GFP) 释放的 ARGs 和抗生素最多，而妊娠母猪 (GS) 释放的 MGE 最多。 ARGs在不同动物类型中的不同分布主要由mantel test和部分冗余分析（pRDA）反映的微生物群落组成差异决定。猪粪中的优势门是厚壁菌门和拟杆菌门，但变形菌门、拟杆菌门和螺旋藻门在塑造 ARGs 谱中起主导作用。抗生素和重金属可以产生并维持 ARGs 谱，而 ARGs 的增殖和传播可能主要归因于猪粪中的微生物群落。

       Modern swine farms generally contain several animal types and rely extensively on the feed additives, including antibiotics and heavy metals, to augment animal growth. Nonetheless, as an important reservoir of antibiotic resistance genes (ARGs) in the environment, the ARGs emission of each animal type from swine farms has not been characterized. The goal of this study is to determine which animal type contributes the most to the ARGs emission into the environment in typical swine farms of China. Results showed that chlortetracycline (CTC), Cu and Zn were the typical feed additives, and the concentrations of antibiotics and heavy metals in the feed and swine manure were generally higher in nursery pigs (NP) than other animal types, while the gene copies of ARGs from gestation sows (GS) were the most abundant. GS released the most of antibiotics, ARGs and mobile genetic elements (MGEs) per head per day compared to other animal types. A typical swine farms with the feedstock of 10,000 pigs could release about 4.0 ± 1.3 × 1017 gene copies of ARGs per day, and concerning the breeding ratio and manure production coefficient, growing and fattening pigs (GFP) released the most of ARGs and antibiotics, whereas gestation sows (GS) released the most of MGEs. The different distribution of ARGs in different animal types was mainly determined by the discrepancy of microbial community composition reflected by mantel test and partial redundancy analysis (pRDA). The dominant phylum in swine manure were Firmicutes and Bacteroidetes, but Proteobacteria, Bacteroidetes and Spirochaetae played the dominant role in shaping the ARGs profiles. Antibiotics and heavy metals could have generated and maintained the ARGs profiles, whereas the proliferation and spread of ARGs could be mainly attributed to microbial community in swine manure.

https://www.sciencedirect.com/science/article/abs/pii/S0048969718350204