Effects of additives containing a novel strain on the fermentation characteristics, structural carbohydrates, and α-tocopherol content of rice straw and corn stover silages

Abstract

Abstract A novel α-tocopherol-producing bacteria strain was isolated and identified as Bacillus tequilensis QH1 (QH1). The effects of QH1 strain inoculation alone (QH), combined with cell wall degradation enzyme (QC), or Lactiplantibacillus plantarum subsp. plantarum YM3 and cell wall degradation enzyme (QLC) as the additives on the fermentation characteristics, structural carbohydrates, and α-tocopherol content of rice straw and corn stover silages were investigated, and without additives as the control (CON), in 4 replicates. After silages were kept in a laboratory cabinet (26–34 ℃) and the dark for 42 d, experimental silos (polyethylene plastic bags) were opened for analysis. The results exhibited that the control and additives-treated rice straw and corn stover were ensiled well, indicated by high lactic acid content and little butyric acid content. The QH and QC degraded structural carbohydrates, demonstrated by lower (P < 0.001) neutral detergent fiber (NDF) and acid detergent fiber (ADF) than the control, but did not enhance lactic acid fermentation, evidenced by lower (P < 0.001) lactic acid content in QH-treated silages compared with the control silages. The effect of QLC on degrading structural carbohydrates was influenced by material factors, evidenced by no role in decreasing the contents of NDF and ADF in rice straw silage and a good role in decreasing the contents of NDF and ADF in corn stover silage. However, the water-soluble carbohydrate (WSC) contents in both rice straw and corn stover silages were increased (P < 0.001) by QLC compared with the control. The control and additives-treated silages had much higher (P < 0.001) α-tocopherol content and lower (P < 0.001) chlorophyll content compared with the material before ensiling. Compared with the control, higher α-tocopherol content was found in QH-treated rice straw (P = 0.071) and corn stover silages (P < 0.05), and QLC-treated corn stover silage (P < 0.05). Therefore, the QH1 strain had the potential to be applied in rice straw silage production, and QLC was recommended to be applied in corn stover silage production. Graphical Abstract

Keywords

• Bacillus tequilensis
• Chlorophyll
• α-Tocopherol
• Structural carbohydrates