紫花苜蓿和鸭茅混合青贮贮藏过程中发酵品质的动态变化

The dynamics of fermentation quality of mixed silage of alfalfa and dactylisin the process of ensiling

为探究紫花苜蓿和鸭茅混合青贮过程中发酵品质的动态变化及添加剂对其影响,试验将紫花苜蓿和鸭茅按照5􀏑5的比例混播后收获,试验处理设对照组(CK)、植物乳杆菌组(Lactobacil⁃lus plantarum,LP),糖蜜组(T),植物乳杆菌+糖蜜混合处理组(LP+T)。分别在贮藏1、3、7、15、30、45、60 d开封,测定其pH值、乳酸、乙酸、丙酸、丁酸和氨态氮含量。结果表明,各组青贮3 d内pH值下降迅速,青贮7 d内乳酸、氨态氮含量迅速增加。发酵45 d后各指标趋于稳定,均未检出丁酸。与CK组相比,添加植物乳杆菌、糖蜜和植物乳杆菌+糖蜜的3个组均可降低紫花苜蓿和鸭茅混合青贮饲料的pH值和氨态氮含量(P<0.05),其中单独添加糖蜜组和混合添加植物乳杆菌+糖蜜组效果最明显,单独添加植物乳杆菌组降低乙酸含量效果显著(P<0.05)。综上,添加植物乳杆菌、糖蜜和植物乳杆菌+糖蜜3种处理均能在一定程度上改善紫花苜蓿和鸭茅混合青贮饲料发酵品质。其中添加糖蜜的紫花苜蓿和鸭茅混合青贮在30 d时取得最佳的发酵品质,其pH值、氨态氮和丁酸含量最低,乳酸含量较高。

The aim of this experiment was to explore the effects of additives on the dynamics of the fer⁃mentation quality of mixed silage of alfalfa and dactylis(at a ratio of 5􀏑5).The experimental treat⁃ments included control group(CK)and Lactoba⁃cillus plantarum treatment group(LP),molasses treatment group(T),and Lactobacillus plantarum+molasses mixed treatment group(LP+T).The silage bags were opened after 1,3,7,15,30,45,and 60 days of storage,and the pH value,lactic acid, acetic acid, propionic acid, butyric acid and ammonia nitrogen contents were measured.The results showed that the pH values dropped rapidly in the first 3 days of ensiling, and the contentof lactic acid and ammonia nitrogen increased rapidly in the first 7 days of ensiling. The fermentationbecame stable and no butyric acid was detected after 45 days of ensiling. Compared with the controlgroup, the three treated groups withLactobacillus plantarum , molasses, andLactobacillus plantarum +molasses decreased the pH values and the ammonia nitrogen contents of mixed silage, which means abetter fermentation quality. The improvement effect of adding molasses and mixing Lactobacillus plan⁃tarum + molasses is the most obvious. Adding Lactobacillus plantarum alone significantly decreasedthe acetic acid contents. In summary, all the three additives partially improved the fermentation quali⁃ty of alfalfa and orchardgrass mixed silage. Among them, the molasses-added mixed silage showed thebest fermentation quality after for 30 days. Indicated by the lowest pH value, ammonia nitrogen andbutyric acid content, higher lactic acid contents.