Study On Fermentation Quality And Microbial Diversity Of Jerusalem Artichoke Residue And Grain Stillage Mixed Silage

China is a large agricultural production country.The agricultural production processing industry developed rapidly.The by-products of agricultural products processing have many characteristics such as large output,great variety and grow rapidly.This kind of food industrial wastes and agricultural products processing residues contain a variety of nutrients,energy and available substances,which have high comprehensive utilization value.Therefore,the comprehensive utilization of by-product resources can greatly improve the added value of agricultural products,and also enhance the competitiveness of agricultural products processing industry.It has good prospects in achieving sustainable development and reducing environmental pollution.In order to solve the problem of discarding by-products,the mixed silage fermentation of grain stillage and Jerusalem artichoke residue was carried out for 60 days based on the silage principle.Eight mixing ratios(1:0,4:1,2:1,1.2:1,1:1.5,1:2.7,1:7,0:1)were set up.They were named group SJ,group M3,group M4,group M5,group M6,group M7,group M8 and group SY in turn.The nutritional components,lignocellulosic components and fermentation characteristics were analyzed dynamically at 10 d,30d and 60 d,respectively.The diversity of bacteria and fungi was analyzed by HiSeq2500 high-throughput sequencing during storage.The research results mainly include the following aspects:1.The results of nutrient components during silage showed that the dry matter content were better preserved after 60 days in groups M3,M4,M5,M7 and SY.The crude protein content increased significantly in group SY(P<0.05),while the crude protein loss ranged from 1.18% to 2.35% DM in others after 60 days.Starch content increased significantly in groups M3~M6 after 60 days(P<0.05).The content of water soluble carbohydrate in groups M5 and M6 were significantly higher than other groups(P<0.05).The water soluble carbohydrate loss rates of groups M5 and M6 were 16.94% and 16.43% respectively.In conclusion,groups M5 and M6 were conducive to the preservation of nutrient components after 60 days.2.The results of lignocellulosic components during silage showed that the contents of NDF and HC in group M5 decreased significantly after 60 days(P<0.05).The contents of ADF and CL in group M6 decreased significantly after 60 days(P<0.05).The contents of ADL in groups SJ and M5 decreased significantly(P<0.05).In conclusion,groups M5 and M6 were conducive to the degradation of structural carbohydrates after 60 days.3.Fermentation characteristics during silage showed that the pH value of groups SJ,M3,M4,M5,M6 and M7 were in a good range(3.8~4.2)after 60 days.The AN/TN value of groups SJ,M3,M4 and M5 were significantly lower than other treatments(P<0.05).Thelactic acid content of all treatments were higher than 3% DM.The content of acetic acid increased with the increase of Jerusalem artichoke residue proportion.And propionic acid,butyric acid,valeric acid and other organic acids were not detected.In summary,the fermentation characteristics of groups SJ,M3,M4 and M5 were better than those of groups M6,M7,M8 and SY after 60 days.4.The results of bacterial diversity during silage showed that the species richness of groups M3,M4,M5,M6 and M7 were high according to OTU statistics and Alpha diversity analysis after 60 days.The dominant phylum-level bacteria in six mixed storage groups and group SY were Firmicutes.The group SJ also evolved from Proteobacteria to Firmicutes.Lactobacillus was the dominant bacteria in six mixed storage groups and group SY.The relative abundance of Lactobacillus was more than 70% after 60 days.The dominant genus-level bacteria in group SJ evolved from Acinetobacter(10d)and Shigella(30d)to Lactobacillus(60d).Compared with groups SJ and SY,the diversity of lactic acid bacteria increased in six mixed silage treatments of Jerusalem artichoke residue and grain stillage,mainly including Lactobacillus,Pediococcus,Bifidobacterium,Enterococcus,Lactococcus,Staphyoccus and Streptococcus.The correlation between fermentation quality and bacterial diversity showed that ADL,ADF,CP,AN/TN and LA contents were positively correlated with the relative abundance of Lactobacillus.The content of AA was positively correlated with the relative abundance of Bacillus.5.The results of fungal diversity during silage showed that compared with those before silage,the fungal species richness and community diversity increased according to fungal OTU statistics and Alpha diversity analysis after 60 days.During the fermentation,the dominant phylum-level of the eight treatments were Ascomycota.The dominant genus-level were Kluyveromyces and Saccharomycetales.The correlation between fermentation quality and fungal diversity showed that the relative abundance of Kluyveromyces was positively correlated with CP content and pH value.In conclusion,the fresh weight-mass ratio of grain stillage to Jerusalem artichoke residue is 1.2:1(group M5)have relatively good quality.It is beneficial to the preservation of nutrient components and the degradation of structural carbohydrates.