Additives improve the fermentation quality, anthocyanin content, and biological activity of purple Napier grass silage

BACKGROUND Purple Napier grass (PNG), a widely used grass rich in anthocyanin, is commonly employed in the production of silage. However, there is currently limited research on the retention of anthocyanin with or without additives during ensiling. Therefore, this study aimed to investigate the effect of different additives (Lactiplantibacillus plantarum CCZZ1 (LP), glucose, acetic acid, and dried soybean curd residue) on fermentation quality, anthocyanin content, and microbial community structure of PNG silage. RESULTS Ensiling PNG without additives led to poor fermentation quality and rapid degradation of anthocyanin, resulting in a decline in antioxidant activity and the persistence of harmful microorganisms with high relative abundance. The use of additives, especially LP, effectively increased the relative abundance of L. plantarum, enhancing fermentation quality, the retention of anthocyanin (up to 166% increase rate) and antioxidant activity, while reducing the relative abundance of harmful microorganisms during ensiling for 30 days. Additionally, prolonged ensiling negatively affected the preservation of anthocyanin. Based on both fermentation quality and bioactivity, PNG should be ensiled for 30 days with LP inoculation. CONCLUSION The employment of additives, especially LP, improved the fermentation quality, anthocyanin retention, and microbial community structure in PNG silage. To optimize both fermentation quality and bioactivity, it is recommended that PNG be ensiled for 30 days with LP inoculation. © 2024 Society of Chemical Industry.