Microbial community structure, co-occurrence network and fermentation characteristics of woody plant silage

BACKGROUND Feed shortage is a factor restricting animal production in the tropics, therefore how to use natural woody plant resources as animal feed is an important strategy. RESULTS Under the dual stress of an anaerobic and acidic environment, the microbial response during the fermentation of paper mulberry (PM) silage was found to be sensitive. The Gram-negative bacteria and mould died, and the dominant microbial community rapidly shifted to Gram-positive bacteria, resulting in a large reduction in microbial diversity and abundance. Exogenous bran additives interfered with the stress effects of the woody silage environment. Wheat bran (WB) accelerated the response of microorganisms to the anaerobic stress, and lactic acid bacteria became the dominant microbial community, thereby enhancing the lactic acid fermentation of silage, affecting the metabolic pathways of microorganisms, and improving the flavour and quality of the silage. Addition of rice bran made Enterobacter and Clostridium species quickly respond to the stress of the silage environment and become the predominant bacterial groups. In particular, anaerobic and spore-forming Clostridium species showed a strong tolerance to the silage environment, leading to butyric acid fermentation and protein degradation of the silage, and reducing its fermentation quality. CONCLUSION The PacBio single-molecule real-time (SMRT) sequencing technology accurately revealed the microbial co-occurrence network and fermentation mechanism of silage. Our results indicate that PM can be used in combination with WB to prepare high-quality silage for animal production. (c) 2021 Society of Chemical Industry.

Automated summary

The research showed that the microbial response and nutrient content of woody plant silage are significantly influenced by the anaerobic and acidic environment, with exogenous bran additives accelerating lactic acid fermentation and improving silage quality, while rice bran addition may lead to butyric acid fermentation and protein degradation, reducing the fermentation quality.