Monensin Inhibits Nitrogen Recycling During Crop Straw Feeding-Substrate Fermentation-Mushroom Cultivation

Abstract

The objective was to evaluate effects of feeding monensin on N recycling during 'straw feeding-substrate fermentation-mushroom cultivation.' During fermentation, Agaricus bisporus was cultivated on mixtures of manure (with or without monensin) and straw (corn or wheat). Rates of N retention were higher for residual monensin (P = 0.016) and for corn straw (P <0.001). During cultivation, there was an interaction (P < 0.001) between straw and antibiotic on N retention rate. However, residual monensin reduced (P < 0.001) N recycling during whole recycling system, due to changes in N transformation-associated enzyme activity, ammonification and denitrification. Specifically, residual monensin altered the microbial community structure and succession, inhibited growth of dominant bacterial phylum Bacteroidetes and fungal phylum Neocallimastigomycota, and increased bacterial phylum Actinobacteriota and Firmicutes. In conclusion, residual monensin in manure decreased the N recycle rate in recycling system, but reduced N losses during fermentation by inhibiting ammonification and denitrification

Keywords: antibiotic, microbial community, Nitrogen transformation, Waste reuse, Solid-state fermentation