Screening Identification And Application Of Main Microorganisms In Alfalfa Silage

As the most important source of crude feed protein for ruminants,alfalfa can maintain its high feed value through silage.The purpose of this study is to make silage alfalfa feed,analyze its main microbial composition,screen the main fermentation bacteria of silage clover according to the analysis results,and select the dominant bacteria of silage clover to modulate high moisture silage clover.Evaluation of the effects of bacteria and different combinations on the quality of silage Medicago sativa.Firstly,semi-dry silage technology was used to modulate and score silage alfalfa,and the number of microbial population and community composition in silage alfalfa were analyzed according to macrogenome sequencing technique.According to the analysis results,using MRS,NA,LB,PDA and McDonnell medium,aerobic and anaerobic culture methods were used to screen microbial strains from natural silage alfalfa fodder.The species and genera of the selected microbial strains were identified by morphology and molecular biology.The results showed that in semi-dry silage with excellent sensory score,the main microbial communities(identified to genus level)were oceanobacillus,Lactobacillis and Bacillis,.They accounted for 24.9%,14.3%and 13.9%,respectively.A total of 30strains were isolated from different media under aerobic and anaerobic conditions at37?,Determined by morphology and conservative sequence alignment,Among them,15 strains were Lactobacillus plantarum,,8 strains were Bacillus subtilis;2 strains were Bacillus licheniformis;Streptococcus lactis,Enterococcus faecium,Bacillus amyloliquefaciens,Bacillus pumilus and Bacillus amyloliquefaciens 1 strain each.The screened strains and identification results were consistent with the results of macro-genome sequencing,which showed that the dominant microflora in silage alfalfa were lactic acid bacteria and Bacillus.Lactobacillus plantarum,Streptococcus lactis,Bacillus subtilis and Bacillus amyloliquefaciens were selected,and Lactobacillus plantarum and Streptococcus lactis were selected according to the proportion of living bacteria at 1:1,1:2 and 2:1respectively;Lactobacillus plantarum,Bacillus subtilis and Streptococcus lactis were in proportion to the number of living bacteria at 2:1:1,1:1:1 and 4:1:1,respectively.Lactobacillus plantarum,Bacillus amyloliquefaciens and Streptococcus lactis were combined at 2:1:1,1:1:1 and 4:1:1.The total amount of compound bacteria was1.0×10~7cfu/g fresh weight,and the fresh Alfalfa was prepared by the combination of Lactobacillus plantarum,Bacillus amylolyticus and Streptococcus lactis.After the preparation,the fermentation quality was evaluated,and the ratio of ammonia nitrogen to total nitrogen(NH-N/TN),total acid and pH value were determined.The results showed that in sensory evaluation,The sensory scores of Lactobacillus plantarum,Streptococcus lactis at 1:1,1:2,and Lactobacillus plantarum,Bacillus amyloliquefaciens and Streptococcus lactis were significantly higher than those in the natural fermentation group(P<0.05).The sensory scores of Lactobacillus plantarum,Bacillus subtilis and Streptococcus lactis were significantly lower than those in the natural fermentation group(P<0.05).In NH-N/TN,except for the proportion of Lactobacillus plantarum,Bacillus subtilis and Streptococcus lactis at4:1:1,the ratio of Lactobacillus plantarum,Bacillus subtilis and Streptococcus lactis was lower than that of natural fermentation group,but the difference was not significant(P<0.05).In pH value,except for the proportion of Lactobacillus plantarum,Bacillus subtilis and Streptococcus lactis at 4:1:1,the other treatments were significantly lower than those in the natural fermentation group(P<0.05).In terms of total organic acid,the volume combination at 1:1:1 was significantly lower than that in the natural fermentation group(P<0.05),and the volume combination at 1:1:1 was significantly lower than that in the natural fermentation group(P<0.05),and the other combinations were significantly higher than those in the natural fermentation group.(P<0.05).The sensory score of silage alfalfa in each experimental group with microbial bacteria was excellent,which indicated that the combination of microbial bacteria with Lactobacillus plantarum as the main strain could effectively improve the sensory score of silage alfalfa fodder.It can reduce the content of ammonia nitrogen and increase the content of total organic acid,which is beneficial to the modulation and quality improvement of silage alfalfa.