添加乳酸菌制剂和糖蜜对箭筈豌豆和苇状羊茅混合青贮发酵品质的影响

Effects of inoculant and molasses additives on fermentation quality of mixed silages of tall fescue( Festuca arundinacea Schreb.) and common vetch( Vicia sativa L.)

[目的]本文旨在评价添加乳酸菌和糖蜜对箭筈豌豆和苇状羊茅混合青贮发酵品质的改善效果。[方法]将处于抽穗初期的苇状羊茅和处于结荚期的箭筈豌豆以7∶3(鲜质量比)混合青贮,并单独或组合添加乳酸菌制剂(10~6CFU·g^(-1))和糖蜜(4%),分别在青贮后的第7、24、45和60天开窖取样,分析混合青贮饲料发酵品质的动态变化。[结果]与对照组相比,单独添加乳酸菌制剂对混合青贮发酵品质的改善效果不明显,而糖蜜或糖蜜+乳酸菌制剂显著提高了乳酸含量(P<0.05),降低了p H值和氨态氮含量,其中糖蜜+乳酸菌制剂组乳酸含量在青贮第7天已显著高于其他各组(P<0.05),并在整个青贮过程中保持最高水平。青贮过程中,各处理组仅检测到微量丙酸和丁酸,并始终显著低于对照组(P<0.05)。[结论]添加糖蜜+乳酸菌提高了青贮饲料的发酵品质,可确保青贮饲料长期保存。

[Objectives]The aim of this study was to assess the effect of adding inoculants or/and molasses on the dynamics of fermentation characteristics of mixed silages of common vetch and tall fescue during ensiling. [ Methods ] Mixture of tall fescue and common vetch （ 7 ： 3 ） were ensiled and treated with distilled water （ control ）, inoculant （ LAB, 2 mL· kg^-1）, molasses （ M, 4% ） and inoculant＋molasses （M ＋LAB）prior to ensiling. [ Results ] Compared with the control, there was no significant effect on improving fermentation quality of mixed silages with inoculant. The addition of M and M ＋LAB significantly （P〈 0.05 ）increased lactic acid contents and significantly（P〈0.05）decreased pH and ammonia content as compared with control. The lactic acid content in M＋LAB began to be higher than other treatments on day 7 of ensiling, and remained the highest value among treatments until the end of ensiling. The concentrations of butyric and propionic acid in silages treated with inoculants or/and molasses were significantly（P〈0.05） lower than those of control during the ensiling. [ Conclusions] The inoculant＋molasses treatment improved the fermentation quality and ensured the long-term preservation of mixed silages.