乳酸菌添加剂对不同生育期菊芋茎叶青贮发酵品质的影响

Effect of growth stage and lactic acid bacteria additives on quality of Jerusalem artichoke silage

为了研究乳酸菌添加剂对不同生育期菊芋(Helianthus tuberosus)茎叶青贮发酵品质的影响,本研究分别在孕蕾前期和开花期采集整株菊芋地上茎秆,带回实验室待水分降至65%左右时,切碎装袋青贮。试验设两个处理组,即对照组(不添加乳酸菌组,CK,0 cfu·g–1)和乳酸菌添加组(LAB,5×106 cfu·g–1),青贮60 d后开封,对青贮饲料进行感官评定和实验室营养成分分析评定。结果表明,1)在菊芋开花期,添加乳酸菌组青贮饲料的pH、氨态氮/总氮比值显著降低,乳酸、乙酸含量显著升高(P <0.05);但在孕蕾前期添加乳酸菌其乳酸含量显著降低(P <0.05),乙酸含量、氨态氮/总氮比值显著升高(P <0.05)。2)菊芋开花期较孕蕾前期茎叶青贮后pH、乙酸、粗灰分含量、体外干物质消化率显著降低(P <0.05),而乳酸、可溶性糖含量显著升高(P <0.05)。以上结果说明,菊芋开花期刈割添加乳酸菌做青贮能够获得较高的发酵品质。

The effect of growth stage and lactic acid bacteria additives on fermentation quality and nutritional value of Jerusalem artichoke silage were studied. Fresh artichokes at two different growth stages (early bud stage and blooming stage) were ensiled, with (5 × 106 cfu·g^–1 LAB) or without a lactic acid bacteria additive, in poly bags for 60 d. The results were as follows: 1) During the blooming period of the Jerusalem artichoke, the pH and ammonia-nitrogen/total nitrogen value of the silage added by the lactobacillus significantly decreased (P < 0.05), while the contents of lactic acid and acetic acid significantly increased (P < 0.05). In addition, the content of lactic acid was significantly decreased (P < 0.05), while the content of acetic acid and the ammonia-nitrogen/total nitrogen value were significantly increased (P < 0.05) in the lactic acid supplementation group of artichokes in the early bud stage. 2) Compared with silage from artichokes harvested in the early bud stage,pH, acetic acid, crude ash, and in vitro dry matter digestibility of silage from artichokes harvested in the blooming stage decreased significantly (P < 0.05), and the lactic acid and water-soluble carbohydrate contents increased significantly (P < 0.05). It can be concluded that addition of lactic acid bacteria to Jerusalem artichoke during the blooming period led to higher fermentative quality.