Abstract:

[Objective] This study aimed to assess the effects of adding different proportions of cassava alcohol residue on fermentation quality of micro-silage of Pennisetum purpureum Schum. cv. Gui Min Yin. [Method] Four treatment groups with different addition levels of cassava alcohol residue were set up using Pennisetum purpureum Schum. cv. Gui Min Yin as raw material. The proportions of Pennisetum purpureum Schum. cv. Gui Min Yin to cassava alcohol residue included in this study were 1∶1.38 （group Ⅰ）, 1∶1 （groupⅡ）, 1∶0.35 （group Ⅲ） and 1∶0.11 （group Ⅳ）. The initiative water content of the micro-silage was set to 40% （group Ⅰ）, 50% （group Ⅱ）, 60% （group Ⅲ) and 70% （group Ⅳ）. Commercial microbial additives were used to prepare mixed micro-silage. Single microbial fermentation of Pennisetum purpureum Schum. cv. Gui Min Yin without addition of cassava alcohol residue was set as the control group （CK group）. There were three replicates for each group. After 30 d fermentation, samples of the fermented micro-silage were taken to assess the sensory indicators, fermentation quality, nutritional components and digestibility. [Result] The sensory indicators of the prepared micro-silage with addition of different proportions of cassava alcohol residue were all better than those of CK group, with group Ⅱ being the best. The dry matter content among the varied groups were significant （P<0.05） different. In comparison to the other groups, the crude protein content in groups Ⅰ and Ⅱ was significantly （P<0.05） higher, and the crude ash content in groups Ⅰ and Ⅱ was significantly （P<0.05） lower. The content of neutral detergent fiber in group Ⅱ was significantly （P<0.05） lower than that in the other groups, and the content of acidic detergent fiber in group Ⅱ was significantly （P<0.05） lower than that in groups Ⅰ, Ⅳ and CK. The soluble carbohydrate content in groups Ⅰ, Ⅱ and Ⅲ was significantly （P<0.05) higher than that in groups Ⅳ and CK. The starch content in group Ⅱ was significantly （P<0.05） higher than that in the other groups. The calcium content in groups Ⅰ, Ⅱ and Ⅲ was significantly （P<0.05） higher than that in CK group, with group Ⅱ being the highest. In comparison to CK group, groups Ⅰ, Ⅱ and Ⅲ had significantly （P<0.05） lower levels of phosphorus. The contents of magnesium, potassium and chloride ions in groups Ⅰ, Ⅱ, Ⅲ and Ⅳ were significantly （P<0.05） lower than those in CK group. The 30 h in vitro dry matter digestibility of groups Ⅰ, Ⅱ and Ⅲ was significantly （P<0.05） higher than that of groups Ⅳ and CK, with group Ⅱ being the highest. Compared with CK group, the lactic acid content of the micro-silage of the cassava alcohol residue addition treatment groups was significantly （P<0.05） increased, while the acetic acid content was significantly （P<0.05） decreased. The ammonia content in groups Ⅰ and Ⅱ was significantly （P<0.05） lower than that in the other groups. [Conclusion] The addition of cassava alcohol residue improves the fermentation quality of the micro-silage of Pennisetum purpureum Schum. cv. Gui Min Yin. When the proportion of Pennisetum purpureum Schum. cv. Gui Min Yin to cassava alcohol residue is 1∶1 and the initiative water content is 50%, the fermentation quality of the micro-silage is the best.

Key words: Pennisetum purpureum Schum. cv. Gui Min Yin, cassava alcohol residue, mixed micro-silage, fermentation quality