Regulation of Pseudomonas sp. PSC001 on the Artificial Rumen Environment Contaminated by Zearalenone

In this study, the RUSITEC system was used to study the regulation of rumen-derived <i>Pseudomonas</i> sp. PSC001 (PSC001) on the rumen environment contaminated by Zearalenone (ZEN). The rumen fluid of dairy cows was selected as the fermentation broth, and four experimental groups were set up: control group (CON), <i>Pseudomonas</i> group (PS), ZEN pollution group (ZEN), and PS and ZEN co-treatment group (PS + ZEN). The NH₃-N, microbial protein (MCP), and volatile fatty acid (VFA) in the rumen fermentation broth were measured after culturing, and the changes in microbial community structure in rumen fluid were analyzed by 16S rRNA gene sequencing. After adding PSC001, the concentration of propionic acid, valeric acid, and butyric acid increased, and the acetate to propionate ratio and concentration of isovaleric acid decreased. ZEN exposure can lead to an abnormal increase in NH₃-N, valeric acid, and isovaleric acid content and a decrease in MCP content. The content of NH₃-N, valeric acid, and isovaleric acid decreased and the content of MCP increased in the PS + ZEN combined treatment group. The addition of PSC001 and ZEN significantly or extremely significantly increased the abundance of 18 genera and significantly or extremely significantly decreased the relative abundance of 5 genera in rumen fluid, respectively. It is worth noting that with the addition of both at the same time, the abundance of four genera in the PS + ZEN group was significantly or extremely significantly increased among the five genera with decreased abundance in the ZEN group. Among the 18 genera with increased abundance in the ZEN group, 10 genera in the PS + ZEN group decreased significantly or extremely significantly. In summary, the addition of PSC001 alleviated the negative impact of ZEN on the internal environment of rumen fermentation, and it also had a positive regulatory effect on rumen fermentation.