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

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2 cm,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(24 cm×40 cm)中,每袋1 kg,然后用真空包装机抽真空封口,室温贮藏45 d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。

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

A study has been undertaken to investigate the effects of probiotics on the fermentation quality,nu-trition composition and in situ ruminal degradability of corn stalk silage.Green corn stalk without ears (dry matter=42%-44%)was chopped to 2 cm 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 cm×40 cm)using a vacuum packager.After 45 days of fermentation at room temperature,the corn stalk si-lage’s 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 (NH 3-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,NH 3-N content,neutral detergent fiber (NDF),acid detergent fiber (ADF),and cellulose content of the cellulase treatments (CE1 and CE2 )significantly decreased (P <0.05 ). Furthermore,the acid detergent lignin (ADL)content had a decreasing trend (P >0.05).The mixture of cel-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.