This study employed high-throughput quantitative polymerase chain reaction to evaluate the effects of specific co-substrate and additive on the fitness of antibiotic resistome during swine manure composting. The results showed that corncob particle as a co-substrate significantly reduced the relative abundances of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) simultaneously. The diversity of ARGs was also reduced more effectively by corncob addition. Brick granule as an additive reduced the concentrations of bioavailable Cu and Zn. However, the relative abundances of ARGs and MGEs were not reduced by the addition of brick granule subsequently. Redundancy analysis indicated a negative effect of the C content and positive effects of class I integrase gene (intI) and bioavailable metals on the variation of the relative abundance of ARGs (p < 0.01). The Procrustes test showed a higher goodness-of-fit between the relative abundance of ARGs and 16S rRNA genes (r = 0.8166; p < 0.0001). Our results suggests that the effect of corncob particle on the relative abundance of ARGs was achieved by driving the changes in physicochemical properties and microbial communities. This study confirmed the hypothesis of fitness cost and demonstrated the contribution of extra C source to ARG attenuation during composting.

本研究采用高通量定量聚合酶链反应评估猪粪堆肥过程中特定共底物和添加剂对抗生素抗药性的适应性。结果表明，玉米芯颗粒作为共底物同时显着降低了抗生素抗性基因（ARGs）和移动遗传元件（MGEs）的相对丰度。添加玉米芯还可以更有效地降低ARGs的多样性。砖颗粒作为添加剂降低了可生物利用的铜和锌的浓度。然而，随后添加砖颗粒并没有降低ARGs和MGEs的相对丰度。冗余分析表明C含量有负面影响，I类整合酶基因有积极影响（intI）和生物利用金属对ARGs相对丰度的变化（p <0.01）。Procrustes试验显示ARGs和16S rRNA基因的相对丰度之间具有较高的拟合优度（r = 0.8166； p <0.0001）。我们的结果表明，玉米芯颗粒对ARGs相对丰度的影响是通过驱动理化特性和微生物群落的变化来实现的。这项研究证实了适用成本的假设，并证明了堆肥期间额外的碳源对ARG衰减的贡献。