微生态制剂对玉米秸秆青贮发酵品质、营养成分及瘤胃降解率的影响

Effects of microecological agents on the fermentation quality,nutrition composition and in situ ruminal degradability of corn stalk silage

本研究以玉米秸秆为研究对象,探讨酶制剂、菌制剂以及酶制剂与菌制剂混合处理对玉米秸秆青贮料发酵品质、营养成分以及瘤胃降解率的影响。玉米秸秆（干物质含量为42%~44%）用青贮切碎机切短至2cm,将各处理青贮剂溶于蒸馏水,与原料混合均匀后,装入聚乙烯袋（24cm×40cm）中,每袋1kg,然后用真空包装机抽真空封口,室温贮藏45d后开封取样。采用实验室化学分析法及半体内试验测定发酵品质、营养成分和瘤胃降解率。结果表明,1）与对照组相比,菌制剂（LAB1和LAB2）处理组pH值和NH3-N含量均显著降低（P〈0.05）,乳酸（LA）含量、有机物（OM）及可溶性碳水化合物（WSC）保存量、干物质（DM）、OM、粗蛋白（CP）的瘤胃降解率显著增加（P〈0.05）;菌制剂处理组的WSC含量显著高于对照组和酶制剂处理（P〈0.05）。2）与对照组相比,酶制剂（CE1和CE2）处理组pH值、NH3-N含量、中性洗涤纤维（NDF）、酸性洗涤纤维（ADF）、纤维素均显著降低（P〈0.05）,乳酸（LA）含量、有机物（OM）及可溶性碳水化合物（WSC）保存量、干物质（DM）、OM、粗蛋白（CP）的瘤胃降解率显著增加（P〈0.05）;有降低酸性洗涤木质素（ADL）含量的趋势,但是差异不显著（P〉0.05）。3）酶菌复合处理组（MCL1和MCL2）pH值最低（P〈0.05）,NDF、纤维素在瘤胃中降解能力显著高于其他处理组（P〈0.05）,ADL降解率在数值上高于其他组,但差异不显著（P〉0.05）;与对照组相比,酶菌混合处理组能够降低NDF、ADF、纤维素含量（P〈0.05）。综上,酶菌复合添加剂喷洒到秸秆中进行青贮发酵后,能够有效破除玉米秸秆青贮饲料的特殊的木质素-纤维素-半纤维素复合体结构,改善秸秆青贮饲料的发酵品质,提高营养物质的保存量及反刍动物瘤胃对秸秆营养物质的降解率,从而提高秸秆的可利用率,其中MCL2处理组效果最佳。

A study has been undertaken to investigate the effects of probiotics on the fermentation quality, nu- trition composition and in sit. ruminal degradability of corn stalk silage. Green corn stalk without ears （dry matter= 42%- 44 %） was chopped to 2 em lengths and then 1 kg of chopped corn stalk was packed with addi- tives （zymin, fungus-preparation, and a mixture of the zymin and fungus-preparation） in polyethylene bags （24 cruX40 era） using a vacuum packager. After 45 days of fermentation at room temperature, the corn stalk si-lagers fermentation quality, nutrition composition and in situ ruminal degradability were analyzed using labora- tory chemical methods and in situ technology. The results showed that, compared to the control, the pH value and ammonia nitrogen （NH3-N） content of the two lactobacillus （LAB1 and LAB2） treatments decreased （P〈 0.05）, whereas contents of lactate acid （LA）, organic matter （OM）, water soluble carbohydrates （WSC）, and the in situ ruminal degradability of DM, OM and crude protein （CP） increased significantly （P〈0.05）. The addition of lactobacillus increased WSC content （P〈0.05） compared with the control and cellulase treatments. Compared with the control, the pH value, NH3-N content, neutral detergent fiber （NDF）, acid detergent fiber （ADF）, and cellulose content of the cellulase treatments （CE3 and CE2） significantly decreased （P〈0.05）. Furthermore, the acid detergent lignin （ADL） content had a decreasing trend （P〉0.05）. The mixture of eel- lulase and lactobacillus treatments （MCL1 and MCL2） had the lowest pH value and the highest in situ degrada- tion of NDF and cellulose compared with other treatments （P〈0.05）. In addition, in situ degradation of ADL increased but did not reach significance （P〉0.05）. Compared with the control, the NDF, ADF and cellulose contents of the cellulase and lactobacillus mixture treatments significantly decreased （P〈0.05）. In conclusion, the application of cellulase and lactobacillus mixtures to the fermentation of corn stalk contributed to the break- down of lignin-cellulose-hemicellulose composite structures and the improvement of fermentation quality, which consequently resulted into high nutrient digestibility and utilization efficiency. The MCL2 treatment had the best effect in this regard.