NZnO-based graphene/graphene oxide compounds inhibit methane metabolic pathways and lower the development of antibiotic resistance genes and virulence factors

Abstract

Ruminant gastrointestinal fermentation produces a large amount of methane (CH4), antibiotic resistance genes (ARGs), and virulence factors (VFs) pose significant risks to human health. This study utilized metagenomic sequencing to investigate the effect of nZnO-based graphene (nZnOG) and nZnO-based graphene oxide (nZnOGO) on the archaeal community, CH4 metabolism, ARGs, VFs, and chemotaxis. Results indicated that the levels of zinc in manure were significantly lower in the nZnOG and nZnOGO groups compared to the nano zinc oxide (nZnO) group. The principal component analysis (PCA) of ARGs antibiotic class showed that there was an 80.13% variation between the three groups, suggesting that different zinc sources could influence ARGs related to various classes of antibiotics. The nZnO group exhibited considerably higher resistance levels to antimicrobial peptides and triclosan, in contrast to the nZnOG and nZnOGO groups. The copy number of ARGs followed the order of nZnO > nZnOG > nZnOGO, with a significant difference observed between the nZnO and nZnOGO groups. Moreover, the nZnOGO group displayed a significantly lower copy number of VFs compared to the nZnO group. Furthermore, the nZnOGO group demonstrated inhibition of CH4 metabolic and chemotaxis pathways, which were associated with reduced transfer of ARGs and VFs. The functional coexistence of ARGs and VFs was driven by the archaeal community, while chemotaxis regulated changes in the archaeal community. These findings suggest that nZnOGO has the potential to inhibit the expression of ARGs and VFs through the inhibition of CH4 metabolism and chemotaxis pathways. Consequently, feed supplementation with nZnOGO may offer a possible solution for mitigating CH4 emission and reducing the transmission of ARGs and VFs.