同/异型发酵乳酸菌对全株玉米青贮营养特征变化的影响

Effects of homo/heterotypic lactic acid bacteria on nutrtional characteristics of whole plant corn silage

为了探讨不同组合同/异型乳酸菌对全株玉米青贮的影响,试验采用真空袋法调制全株青贮玉米,并用乳酸菌对其进行发酵,共分为4组:CK组不加任何菌剂;T组按照1:1比例添加同型发酵乳酸菌植物乳杆菌和乳酸片球菌,添加量均为1×10^(5)cfu/g;Y组添加异型发酵乳酸菌布氏乳杆菌,添加量为1×10^(5)cfu/g;TY组按照1:1:1比例添加同型、异型发酵乳酸菌,添加量均为1×10^(5)cfu/g。对贮存0~60 d的全株玉米青贮的主要微生物数量、发酵指标和营养物质的变化规律进行研究。结果表明:在贮存第8~35天,TY组乳酸菌数量显著高于CK组和Y组(P<0.05);霉菌数量随着贮存时间的延长呈先降低后升高的趋势,在贮存第8天霉菌数量降到最低(<2lgcfu/g),且第35~60天Y组霉菌数量最低;Y组的pH值在第45~60天显著低于其他组(P<0.05);在贮存第35天,乳酸含量最高的是TY组(P<0.05);在贮存第8天,各加菌组乙酸含量显著低于CK组(P<0.05),且在贮存第60天Y组、TY组乙酸含量显著高于T组和CK组(P<0.05);在贮存第15~60天,Y组、TY组的氨态氮含量显著低于CK组(P<0.05);在贮存第60天,Y组干物质含量最高(P<0.05);在贮存第2~8天,TY组的粗蛋白含量最高(P<0.05);在整个青贮过程中,CK组可溶性碳水化合物含量均最高(P<0.05);在贮存第2~15天,加菌组淀粉含量显著低于CK组(P<0.05);在贮存第15,35,60天,T组和Y组中性洗涤纤维含量显著低于CK组和TY组(P<0.05);在贮存第35~60天,加菌组的酸性洗涤纤维含量显著低于CK组(P<0.05)。不同组别和贮存天数的交互作用对乳酸菌的影响显著(P<0.05),对霉菌数量、pH值和乳酸、氨态氮、粗蛋白、可溶性碳水化合物、淀粉含量的影响均极显著(P<0.01),对乙酸、干物质、中性洗涤纤维和酸性洗涤纤维含量的影响不显著(P>0.05)。说明在全株玉米青贮过程中,按照1:1:1比例添加同型、异型发酵乳酸菌和按照1:1比例添加同型发酵乳酸菌能提高乳酸菌的数量、乳酸含量;添加异型发酵乳酸菌对霉菌的抑制效果最好,能减少氨态氮的产生,维持较低的pH值;按照1:1比例添加同型发酵乳酸菌和添加异型发酵乳酸菌能降低中性和酸性洗涤纤维含量,能提高乳酸菌的数量、乳酸含量;添加异型发酵乳酸菌对霉菌的抑制效果最好,能减少氨态氮的产生,维持较低的pH值;按照1:1比例添加同型发酵乳酸菌和添加异型发酵乳酸菌能降低中性和酸性洗涤纤维含量。

In order to investigate the effects of different combinations of homogenous and heterogenous lactic acid bacteria on whole corn silage, the whole silage corn was prepared by vacuum bag method and fermented with different lactic acid bacteria agents, which were divided into 4 groups: No inoculant treatment(CK);Combined with the same type of lactic acid bacteria Lactobacillus plantarum and Pediococcus acidilactici(T) adding 1:1, 1×10^(5)cfu/g;Adding a lactic acid bacteria Lactobacillus buchneri(Y), adding 1×10^(5)cfu/g;Complex homo-and hetero-fermentative lactic acid bacteria, adding 1:1:1(TY). The number of main microorganisms, fermentation characteristics and nutrition subtances indicators from 0 to 60 th day were determined. The results showed that the number of lactic acid bacteria in TY group was significantly higher than those in CK and Y groups at the 8 th to 35 th day of fermentation(P<0.05). The number of mold decreased at first and then increased with fermentation, and reached the lowest value(<2 lg cfu/g) on the 8 th day of fermentation, which was observed in Y group from the 35 th day to the 60 th day. The pH value of Y group was significantly lower than that of other groups at day 45 to 60(P<0.05). On the 8 th day of storage, the acetic acid content in each bacteria adding group was significantly lower than that in CK group(P<0.05), and on the 60 th day of storage, the acetic acid content in Y and TY groups was significantly higher than that in T and CK groups(P<0.05). At the 15 th to 60 th day of sto-rage, the ammonia nitrogen content in Y and TY groups was significantly lower than that in CK group(P<0.05). On the 60 th day, Y had the highest dry matter content(P<0.05). At the 2 nd to 8 th day of storage, the crude protein content in TY group was the highest(P<0.05). In the whole silage process, soluble carbohydrate content in CK group was the highest(P<0.05). At the 2 nd to 15 th day of storage, the starch content in the adding group was significantly lower than that in the CK group(P<0.05). At the 15 th, 35, and 60 days of storage, the neutral detergent fiber content in T and Y groups was significantly lower than that in CK and TY groups(P<0.05). From 35 to 60 days of storage, the acid detergent fiber content in the bacteria adding group was significantly lower than that in CK group(P<0.05). The interaction of different groups and storage days had significant effects on lactic acid bacteria(P<0.05). Mold, pH value, lactic acid, ammonia nitrogen, crude protein, soluble carbohydrate and starch were extremely significant(P<0.01), but there were no significant effects on acetic acid, dry matter, neutral detergent fiber and acid detergent fiber(P>0.05). The results showed that the number of lactic acid bacteria and lactic acid content could be increased by adding homotype and heterotype lactic acid bacteria at the ratio of 1:1:1 during the whole corn silage. The addition of hetero-fermented lactic acid bacteria has the best inhibition effect on mold, which can reduce the production of ammonia nitrogen and maintain a low pH value. The content of neutral and acid detergent fiber can be reduced by adding homogenous and heterogenous lactic acid bacteria in 1:1 ratio.