## 4 Discussion
In the process of ensilage, microbial reactions are violent, and adding different additives will have different effects on the microbial community structure [32]. By using the 16S rRNA high-throughput sequencing technique, we can know the differences in bacterial communities among different additive treatment groups. The \(\alpha\)-diversity can explain the richness, diversity, and evenness of species in bacterial communities. Good's coverage is an index reflecting the depth of bacterial sequencing. Chao1 index and observed species index are used to indicate the richness of community species; the Shannon index and Simpson index are used to indicate the diversity of community species; and Pielou evenness reflects the evenness of the bacterial community. The results showed that the addition of CE and LP significantly reduced Pielou uniformity, Simpson index, and Shannon index. Similar to our research, [PERSON] et al. (2020) found that the OTUs, Shannon index, and Chao1 index of amaranth silage added with CE and LP were lower than those of the control group. It may be that the addition of CE and LP promoted the proliferation of lactic acid bacteria and inhibited the growth of other harmful bacteria [33]. The addition of LP+SU significantly increased the observed species and Chao1 index. The \(\beta\)-diversity can reflect the difference in the bacterial community in each individual or treatment group. It can be seen that there is obvious separation between CE+LP, LP+SU, and CON, indicating that there are differences in bacterial composition among CE+LP, LP+SU, and CON. To sum up, the results of bacterial diversity are consistent with those of fermentation parameters and chemical components. After adding CE and LP on the surface, the structure of silage flora has changed greatly. The bacterial community was closely related to the quality of silage. At the gate level, the dominant bacteria in all treatment groups were _Firmicutes_ and _Proteobacteria_, which was consistent with the result of [PERSON] et al. (2022) [34]. _Firmicutes_ is an important microorganism in silage fermentation, and most of the bacteria involved in LA fermentation belong to _Firmicutes_[35], which can secrete a variety of cellulases, lipases, and proteases [36]. The average contents of _Firmicutes_ and _Proteobacteria_ in LP+SU were significantly different from those of other groups, and the fermentation direction was not consistent with that of other groups. Other gates are less abundant but also play an important role in silage. At the genus level, the dominant bacteria are _Lactobacillus_, _Weissella_, and _Pedicococcus_, which are different from the results of [PERSON] et al. (2022) [34]; the mixed silage of hybrid _Pennisetum_ and mulberry leaves is mainly attached to _Lactobacillus_, _Weissella_, _Pantoea_, and _Leuconstoc_ bacteria during the entire ensiling period. The slightly different dominant bacteria may be due to the different climatic conditions and raw material growth conditions. _Lactobacillus_ is a homoferentative lactic acid bacteria that can consume WSC to produce LA. _Weissella_ is a heterologous fermentator that can consume WSC to produce LA, AA, and CO\({}_{2}\)[37]. It is worth noting that the proportion of _Lactobacillus_ in the CE+LP group is higher than in other groups, but the proportion of LA in this group is the lowest, and the proportion of AA is the highest among all groups. _Lactobacillus_, as a homoferentative genus, will generally consume WSC and produce LA but will convert LA to AA in the absence of sugar [25]. Therefore, the reason may be that cellulase in the early stage of the CE+LP group decomposes more WSC, and the addition of exogenous LP makes LP more advantageous than other groups. However, in the later stage, cellulose loses its activity in a low pH environment [38], making it difficult to produce new WSC. In the later stage, a large amount of LP will consume WSC, and LP metabolites LA into AA when sugar is deficient.