## 4 Discussion
### Effect of Moisture Content and Additives on the Fermentation Quality of AWB Mixed Silage
plantarum_ to the silage process reduced the AN/TN and fungal counts in maize silage and effectively improved the fermentation quality of maize silage. [PERSON] et al. [31] inoculated lactic acid bacteria during the silage of spent mushroom substrate, which improved the fermentation quality. This was explained by the fact that the addition of homofermetative lactic acid bacteria preparations can promote the early entry of silage into lactic acid fermentation, change the situation of insufficient lactic acid bacteria in the early stage of fermentation, and produce large amounts of LA to reduce the pH and AN/TN of silage, thus inhibiting the growth and reproduction of yeasts and molds and reducing nutrient losses [32]. Cellulase can degrade cellulose, hemicellulose, and lignin, which are not easily digested by animals, and hydrolyze cell walls to release contents and increase the fermentation substrate for lactic acid bacteria, improving forage silage quality [33]. The inoculation of alfalfa silage with cellulase resulted in a lower pH and AN/TN and a higher WSC and LA content in a test group compared to a control group, consistent with the results of this study for the tests with E added at 60% and 65% MC conditions [34]. The AN content is mainly related to the degradation of protein and amino acids in silage [35]. A higher AN content indicates more protein and amino acid decomposition and poorer fermentation quality of silage. Under different MC conditions, the AN/TN of each additive treatment group was lower than that in the control group. The explanation was that low pH inhibited harmful microorganisms and plant protease activity, decreased the degree of protein breakdown in AWB mixed silage, and reduced AN production, which was consistent with the findings of [PERSON] et al. [35]. Interestingly, the concentration of AA in the AWB mixed silage was lower in the L group than in the control group at 60% MC. This result contrasted with the results reported by [PERSON] et al. [36], where the AA concentrations of corn silage inoculated with _heterotrophic lactobacilli_ (_Lactobacillus hilgardii_) were significantly higher than those in the control. The explanation is that the differences in lactic acid bacteria species lead to inconsistent fermentation products (AA) of silage, with homofermetative lactic acid bacteria metabolizing only LA, while heterofermetative lactic acid bacteria can produce high concentrations of AA and multiple metabolites. Lactic acid bacteria can reduce the level of AA to improve the palatability of silage. [PERSON] et al. [37] found that inoculation of _L. plantarum_ in mulberry silage reduced the AA content, which was consistent with the results of this study for the experiment with L added at 60% MC. The combined addition of lactic acid bacteria and cellulase can significantly reduce the pH of corn stover silage, which was found to be more effective than the addition of lactic acid bacteria alone [19]. At 60% MC, the pH of AWB mixed silage in the M group decreased by 0.03-0.18 units, AN/TN decreased by 0.19-0.3 units, and LA content increased by 10.4-18.9% compared to the control, L, and E groups. According to [PERSON] et al. [38], a combined lactic acid bacteria and cellulase addition group had the highest LA concentration and the lowest pH of silage compared to control and separate addition groups, which effectively improved the fermentation quality of _Lev minus chinensis_ silage, which was consistent with the results of this study as stated above. Lactic acid bacteria were more effective on silage with high WSC content [39], indicating that the addition of cellulase to increase the WSC content of AWB mixed silage was more beneficial for the improvement in fermentation quality. Thus, the combination of lactic acid bacteria and cellulase exerted a synergistic effect and had a positive effect on improving the fermentation quality of AWB mixed silage.