含水量和添加剂对饲用谷子青贮营养成分和发酵品质的影响

目的]研究预干处理、添加糖蜜和植物乳杆菌混合制剂对饲用谷子青贮营养成分和发酵品质的影响。方法]以灌浆期106号和107号饲用谷子为原料,采用双因素（含水量×添加剂）完全随机试验设计,分别用新鲜及预干处理的谷子调制青贮;利用2种不同含水量的谷子调制的青贮中,无添加为对照组（CK）,添加1%糖蜜和0.2%植物乳杆菌的混合制剂为试验组（ML）,每个处理3个重复,于20~30 ℃室温环境中发酵45 d。开封后测定青贮干物质含量、常规营养成分含量、pH值、乳酸含量及挥发性脂肪酸含量。结果]预干处理极显著（P<0.01）提高2种饲用谷子青贮的干物质含量和pH值,显著（P<0.05）提高106号饲用谷子青贮的中性洗涤纤维含量,同时,极显著（P<0.01）降低乳酸和乙酸含量。106号饲用谷子预干青贮ML组的干物质含量极显著（P<0.01）高于CK组。2种饲用谷子的新鲜和预干青贮ML组的pH值均极显著（P<0.01）低于CK组,乳酸含量极显著（P<0.01）高于CK组。2种饲用谷子预干青贮ML组的乙酸含量显著（P<0.05）高于CK组。结论]预干处理有利于营养成分的保留,但对青贮发酵有一定的抑制作用。添加糖蜜和植物乳杆菌对营养成分无显著影响,但能促进青贮乳酸发酵,显著降低pH值,提高乳酸/乙酸值。

Effects of Water Content and Additive on Nutritional Components and Fermentation Quality of Forage Millet Silage

Objective] To investigate the effects of pre-drying treatment and supplementation of mixed preparations composed of molasses and Lactobacillus plantarum on nutritional components and fermentation quality of forage millet silage. Method] The forage millet varieties of NO.106 and NO.107 harvested at the filling stage were used as materials. A two-factor （water content × additive） completely randomized designed trail was carried out. For both of the millet varieties, the silage was prepared with fresh and pre-dried materials containing different water contents, respectively. The control groups （CK） had no addition of additive, while the experimental groups （ML） had a combined addition of 1% molasses and 0.2% Lactobacillus plantarum. Each treatment had three repeats and fermented for 45 days at room temperature （20-30 ℃）. The contents of dry matter, conventional nutritional components, lactic acid and volatile fatty acids as well as pH value of the unsealed silage were measured after fermentation. Result] Pre-drying treatment extremely significantly （P<0.01） increased the dry matter content and pH value of the two forage millet silage. Furthermore, it significantly （P<0.05） increased the neutral detergent fiber content as well as extremely significantly （P<0.01） decreased the contents of lactic acid and acetic acid of NO.106 forage millet silage. The dry matter content in the pre-dried ML group of NO.106 forage millet silage was extremely significantly （P<0.01） higher than that in its corresponding CK group. The pH value in the fresh and pre-dried ML groups of both forage millet silage was extremely significantly （P<0.01） lower than that in their corresponding CK groups, while the lactic acid content was extremely significantly （P<0.01） higher. The acetic acid content in pre-dried ML groups of both forage millet silage was significantly （P<0.05） higher than that in their corresponding CK groups. Conclusion] Although pre-drying treatment was conductive to retain the nutritional components in the forage millet silage, it had an inhibitory effect on silage fermentation. Addition of molasses and Lactobacillus plantarum had minor influence on nutritional components, but it stimulated the lactic acid fermentation, dramatically lowered pH value, and raised lactic acid/acetic acid value of the forage millet silage.