Effects Of Different Additive Combinations On Silage Quality,growth Performance And Rumen Microbial Community Of Beef Cattle

In order to improve the utilization rate of regional feed resources sugarcane top,this research contents of this thesis include two parts.First,to explore the effects of different additive combinations on the fermentation quality and microbial community of silage sugarcane top;Second,to explore the effects of different additive combinations on the growth performance and rumen microbial community of Holstein beef through animal experiment.Experiment one:the objective of this study was to evaluate the effect of different mixed additives on the fermentation and microbial community of sugarcane top silage.After chopping,sugarcane top was treated as follows:no additives（CK）;Pediococcus acidilactici+Saccharomyces cerevisiae+cellulase+xylanase（T1）;Lactobacillus plantarum+Bacillus subtilis+Aspergillus oryzae（T2）.Each group was set up with 4 repetitions,treated forage was stored for 60 d.The diversity of bacteria and fungi was analyzed by high-throughput sequencing,and the routine nutrient composition and fermentation indexes were determined by laboratory methods.The results showed that:1)Compared with the control group,the T1 group significantly reduced the content of p H,DM and WSC,butyric acid and NH₃-N in sugarcane top silage（P<0.05）,and increased the content of lactic acid,acetic acid and CP（P<0.05）;2)Compared with the control group,the T2 group significantly reduced the content of ADF,WSC,butyric acid and NH₃-N in sugarcane top silage（P<0.05）,and increased the content of lactic acid,acetic acid and butyric acid（P<0.05）;3)Among all treatment groups,the T2 group showed the highest lactic acid,propionic acid content and the lowest butyric acid content;4)Compared with CK,T1 and T2groups decreased the abundance of Proteobacteria and Actinobacteria,respectively（P<0.05）;5)Compared with CK group,the T1 and T2 groups significantly reduced the abundance of Acinetobacter and Bacillus,however,the T2 group significantly increased the abundance of Acetobacter（P<0.05）;6)Compared with CK,the abundance of Basidiomycota increased significantly in T1 group（P<0.05）,while the abundance of Ascomycota decreased significantly in T2 group（P<0.01）;7)Compared with CK,the abundance of Pichia in T1and T2 groups was significantly reduced（P<0.01）,while the abundance of Mortierella increased significantly in T2 group（P<0.01）.Experiment two:the objective of this study was to evaluate the effect of different mixed additives on the nutrient apparent digestibility and rumen microbial community of beef.Eighteen Holstein beeves were randomly divided into groups and fed with sugarcane top of the one experiment.The aim of this study was to investigate the effects of silage sugarcane top with different additives on growth performance and rumen microorganisms of beef cattle.The results show that:1)The average daily gain（ADG）of T1 and T2 groups were significantly higher than CK group（P<0.05）;but the difference in feed intake was not significant（P>0.05）;2)The apparent digestibility of CP and ADF in the T1 and T2 groups were significantly higher than the control group;3)Compared with CK group,the abundance of Bacteroidetes phylum and Prevotella＿1 decreased,and the abundance of Firmicutes and Rikenellaceae-RC9-gut-group increased in T1 and T2 groups,but the difference was not significant（P>0.05）;4)Compared with CK group,the abundance of Ascomycota and Pichia decreased,and the abundance of Neocallimastigomycota and Mortierella increased in T1 and T2groups,but the difference was not significant（P>0.05）.In conclusion,the mixed additives of Pediococcus acidilactici+Saccharomyces cerevisiae+cellulases+xylanase and Lactobacillus plantarum+Bacillus subtilis+Aspergillus oryzae,can increase the content of lactic acid and acetic acid in the silage sugarcane top and the growth performance of of Holstein beef.In addition,the two mixed additives also had a significant effect on the changes in the microbial community abundance in silage sugarcane top and beef rumen.