Macauba palm cake as additive in elephant grass silage

ABSTRACT. The aim of this study was to evaluate the addition of macauba palm cake (Acrocomia aculeata) on the chemical composition, fermentation and aerobic stability of elephant grass silages (Pennisetum purpureum). The experiment was performed in a completely randomized design with four replicates. The treatments were composed of six levels of macauba palm cake (0, 6, 12, 18, 24, 30%) as additive to elephant grass silage. Dry matter and ethereal extract content of the silage increased linearly with the inclusion of the additive. Addition levels of 15.54% would provide 35% of dry mass, and the limit of 7.00% of ethereal extract in the silage could be obtained with 10.47%. The neutral detergent fiber content reduced linearly from 68.97 to 52.59%, but lignin increased linearly from 6.56 to 7.70%. There was a reduction of 0.17% in the ammoniacal nitrogen content for each 1% of cake. The minimum value of dry matter losses (1.33%) was estimated to the inclusion level of 23.70%. The aerobic stability increased with inclusions between 18 and 24% of cake. The use of levels between 10 and 15% of macauba palm cake are sufficient to optimize dry matter and ethereal extract contents of the silages and to provide a high aerobic stability with minimum losses.摘要 本研究旨在评估添加马卡乌巴棕榈饼（macauba palm cake，学名Acrocomia aculeata）对象草青贮料（elephant grass silages，学名Pennisetum purpureum）的化学成分、发酵特性及好氧稳定性的影响。本实验采用完全随机设计，设置4次重复。试验设置6个马卡乌巴棕榈饼添加梯度（0、6、12、18、24、30%）作为象草青贮的添加剂。青贮料的干物质与乙醚提取物（ethereal extract）含量随添加剂添加量呈线性升高。当添加量为15.54%时，青贮料干物质占比可达35%；若要使青贮料中乙醚提取物含量达到7.00%的限值，对应的添加量为10.47%。中性洗涤纤维（neutral detergent fiber）含量从68.97%线性降至52.59%，但木质素含量从6.56%线性升至7.70%。每添加1%的马卡乌巴棕榈饼，氨态氮（ammoniacal nitrogen）含量降低0.17%。经估算，当添加量为23.70%时，干物质损失（dry matter losses）达到最小值1.33%。好氧稳定性在添加18%~24%的马卡乌巴棕榈饼时有所提升。使用10%~15%的马卡乌巴棕榈饼添加量，即可优化青贮料的干物质与乙醚提取物含量，同时获得较高的好氧稳定性且伴随最低的干物质损失。