| In this study,we used initial bloom stage of alfalfa as materials,adding different proportions of corn flour,rice chaff,and wheat bran(10%,15%and 20%),combined with molasses(2%)and microbial inoculants(106cfu/g)to make mixed silage.The pH value,organic acid content such as lactic acid,acetic acid,propionic acid and butyric acid,living microbial count(Lactic acid bacteria,Yeast and Escherichia coli)and Ammonia nitrogen/Total nitrogen(AN/TN)ratios were measured during ensiling(storage at room temperature for 14d and 56d)and after aerobic stability test,to evaluate the fermentation quality and aerobic stability.The bacterial community was analyzed by denaturing gradient gel electrophoresis(DGGE)and to assess the correlation among fermentation quality,aerobic stability and bacterial community of alfalfa silage.The results showed that:(1)When the alfalfa was mixed with different concentrations of corn flour,rice chaff and wheat bran,and with addition of molasses and microbial inoculants,the fermentation quality and aerobic stability of alfalfa silage improved.The addition of 10%corn flour and 2%molasses or addition of 15%corn flour resulted in good fermentation quality and aerobic stability.The bacterial flora distribution indicated that Pantoea agglsomeran was a specific microorganism for corn flour supplementation groups.(2)Although different bacterial community distribution was observed in different batches alfalfa silage,Lactobacillus plantarum and Enterococcus mundtii were the dominant species,which increased the ratio between Lactic acid and Acetic acid,reduced the AN/TN values and improved the fermentation quality of alfalfa silage.(3)The Lactobacillus fructivorans from the molasses group,the P.agglsomeran,Pediococcus pentosaceus and Lactobacillus brevis from corn flour group,and the Pediococcus acidilactici from rice bran group had an effect on improving the aerobic stability.(4)The Bacillus megaterium observed in the control group increased AN/TN value and decreased quality of alfalfa silage,which was probably one of the flora causing aerobic spoilage. |
