Effects Of Lactic Acid Bacteria On Fermentation Quality,Aerobic Stability And Microbial Diversity Of Whole Corn And Soybean Mixed Silage

Whole corn is a grass family with a high sugar content and yield and is drought tolerant,making it easy to silage.Soybean is a leguminous forage with a low soluble carbohydrate(WSC)content,high buffer energy and high antinutritional factor activity,which makes silage alone less effective and less likely to be successful.In principle,mixing the two into silage can make up for their respective deficiencies and improve the quality of the mixed silage.In this experiment,the effects of Lactobacillus plantarum and Lactobacillus brucei as additives on the nutrient composition,fermentation quality,aerobic stability and microbial diversity of whole corn and soybean mixed silage after 14,28 and 56 d were investigated using whole corn and soybean as raw materials to provide a scientific basis to produce high-quality mixed silage.Whole corn and soybean mixed silage was silaged in pastic vacuum-pcked bags made of PA+PE food grade material for 14 d,28 d and 56 d.Three treatment groups with three replicates each were used for the silage of fresh whole corn and soybean mixed silage without any additives(CK group),Lactobacillus plantarum(LP group)and Lactobacillus brucei(LB group).The nutrient content,fermentation quality,aerobic stability and microbial diversity of the mixed silage were determined.The main conclusions were obtained as follows.(1)Different Lactobacillus treatments at the fermentation stage had a significant effect(P<0.05)on the changes in fermentation quality and fermentation characteristics of whole corn soybean mixed silage.Dry matter(DM)and crude Protein(CP)were higher in the Lactobacillus treatment group than in the control group(CK),while soluble carbohydrate(WSC),NDF and acid detergent fibre(ADF)were lower in the treatment group with the addition of Lactobacillus plantarum than in the CK group.Addition of Lactobacillus plantarum and Lactobacillus brucei reduced p H and propionic acid,while addition of Lactobacillus increased LA and AA.different Lactobacillus treatments had significant effects on Lactobacillus and Saccharomyces cerevisiae(P<0.05).(2)The lactic acid bacteria treatment groups were more aerobically stable than the CK group,reaching 66 h,113 h and 145 h in the CK,LP and LB groups,respectively.Lactic acid bacteria treatment groups all improved the aerobic stability of whole plant corn and soybean mixed storage.(3)The addition of different lactic acid bacteria increased the number of lactic acid bacteria(P < 0.05)and decreased the number of yeast(P < 0.05),and the number of lactic acid bacteria and yeast tended to increase with the number of silage days.(4)The bacterial diversity results showed that the type of Lactobacillus and silage time significantly influenced the microbial diversity of whole plant corn soybean mixed silage.At the phylum level the addition of Lactobacillus to whole plant corn soybean silage mix increased the abundance of Firmicutes and decreased the abundance of proteobacteria.Lactobacillus had the highest abundance at the genus level and the relative abundance of Enterobacteriaceae was significantly reduced by the addition of lactic acid bacteria.The dominant bacteria at the species level were Lactobacillus plantarum and Lactobacillus brevis.In conclusion,both Lactobacillus plantarum and Lactobacillus brucei improved silage quality,reduced p H and increased lactic acid production in whole plant corn and soybean silage mixes.Both Lactobacillus plantarum and Lactobacillus brucei were able to increase the abundance of lactic acid bacteria,mainly Lactobacillus spp in whole plant corn and soybean silage during the silage process.Lactobacillus treatment also improved aerobic stability.In this study,the Lactobacillus plantarum treatment and Lactobacillus buchneri treatment gave better mixed silage results than the non-added Lactobacillus treatment and can be recommended as fermenters for whole plant corn soybean mixed silage.