不同微生物菌剂与压实密度对玉米青贮营养成分及发酵品质的影响

Effects of Different Microbial Agents and Compaction Densities on Nutritional Components and Fermentation Quality of Corn Silage

[目的]探究添加不同微生物菌剂及不同压实密度对玉米青贮营养成分及发酵品质的影响。[方法]以全株青贮玉米为原料,选取4种微生物发酵菌剂,设置2个压实密度(750 kg/m^(3)和850 kg/m^(3))和2种微生物菌剂添加方式(推荐添加剂量和相同水平添加剂量)。微生物菌剂A(A组,由粪肠球菌、副干酪乳杆菌等7种菌组成)、B(B组,由布氏乳杆菌、植物乳杆菌组成)、C(C组,由布氏乳杆菌、植物乳杆菌、乳酸片球菌组成)、D(D组,由植物乳杆菌、布氏乳杆菌组成)的推荐添加剂量分别为2.5×10^(11)、1.1×10^(11)、2.9×10^(11)、1.0×10^(12)CFU/t;相同水平添加剂量为5.0×10^(11)CFU/t。2个压实密度下,均设置不添加微生物菌剂的对照组。发酵120 d后取样,测定并比较不同微生物菌剂添加水平及不同压实密度下玉米青贮营养成分和发酵指标。[结果]在750 kg/m^(3)压实密度下,当添加推荐剂量的4种微生物菌剂时,D组干物质含量高于对照组,且显著(P<0.05)高于A组与B组,当4种微生物菌剂添加量均为5.0×10^(11)CFU/t时,D组干物质含量显著(P<0.05)高于对照组;与对照组相比,添加推荐剂量和相同剂量的4种微生物菌剂均有提高青贮粗蛋白、淀粉以及乳酸含量的趋势,2种压实密度下添加推荐剂量微生物菌剂,玉米青贮淀粉含量分别提高了5.61%~9.23%和2.49%~6.71%,乳酸含量分别提高了11.09%~25.94%和15.56%~38.97%。在850 kg/m^(3)压实密度下,当4种微生物菌剂添加量均为5.0×10^(11)CFU/t时,C组和D组青贮干物质含量分别比对照组提高了2.94%和2.60%;与对照组相比,添加推荐剂量和相同剂量的4种微生物菌剂均有降低青贮丁酸含量的趋势。总体来看,不同压实密度对玉米青贮营养成分及发酵品质影响有限。[结论]添加不同微生物菌剂能够提高玉米青贮营养成分及发酵品质,植物乳杆菌与布氏乳杆菌联合使用效果优于多种微生物联合使用效果,且高浓度添加效果更好。

[Objective]The aim of this study was to explore the effects of different microbial agents addition and different compaction densities on nutritional components and fermentation quality of corn silage.[Method]Four commercial microbial agents with two compaction densities(750 kg/m^(3) and 850 kg/m^(3)),and two microbial agent addition methods(adding the recommended level or the same level)were set up using whole plant silage corn as raw material.The recommended addition levels of the microbial agents A(group A,consisting of 7 bacteria such as Enterococcus faecalis and Lactobacillus paracasei),B(group B,consisting of Lactobacillus buchneri and Lactobacillus plantarum),C(group C,consisting of Lactobacillus buchneri,Lactobacillus plantarum and Pediococcus acidilactici)and D(group D,consisting of Lactobacillus plantarum and Lactobacillus buchneri)were 2.5×10^(11),1.1×10^(11),2.9×10^(11) and 1.0×10^(12) CFU/t,respectively.The same addition level of the four microbial agents was 5.0×10^(11) CFU/t.Control groups without addition of microbial agents were set at the both compaction densities.After 120 d fermentation,samples of the corn silage were taken to measure and compare the nutritional components and fermentation indicators under different levels of microbial agents addition and at different compaction densities.[Result]At the compaction density of 750 kg/m^(3),when adding the recommended levels of the four microbial agents,the dry matter content in group D was higher than that in control group,and was significantly(P<0.05)higher than that in groups A and B.When the addition level of the four microbial agents was all 5.0×10^(11) CFU/t,the dry matter content in group D was significantly(P<0.05)higher than that in control group.Compared with control group,adding the recommended levels and the same level of the four microbial agents all had trend of increase in the contents of crude protein,starch and lactic acid.Adding the recommended levels of the four microbial agents at the both compaction densities,the starch content increased by 5.61%to 9.23%and 2.49%to 6.71%,respectively,and the lactic acid content increased by 11.09%to 25.94%and 15.56%to 38.97%,respectively.At the compaction density of 850 kg/m^(3),when the addition level of the four microbial agents was 5.0×10^(11) CFU/t,the dry matter content in groups C and D increased by 2.94%and 2.60%compared to control group,respectively.In comparison with control group,the addition of the recommended levels and the same level of the four microbial agents showed trend of decrease in the content of butyric acid.Overall,different compaction densities had limited effects on the nutritional components and fermentation quality of the corn silage.[Conclusion]Microbial agents addition improves the nutritional components and fermentation quality of corn silage.Higher level addition of the microbial agent consisting of Lactobacillus plantarum and Lactobacillus buchneri has better performance than lower level addition of the microbial agent with the same composition or combinative addition of multiple microorganisms.