Effects Of Adding Lactic Acid Bacteria On The Fermentation Quality Of Whole-plant Corn Silage And Cattle Energy Metabolism

Whole plant corn silage is an important roughage in ruminant industry.The application of lactic acid bacteria additives for ensiling has become the normalcy.In general,the effect of adding lactic acid bacteria additives to improve the fermentation quality of whole corn silage is limited,but inoculation can still improve the production performance of ruminants.In order to study the improvement effect of lactic acid bacteria inoculation on ruminants production,the natural fermentation quality and bacterial diversity of whole plant silage of different varieties were analyzed,and the effect of lactic acid bacteria additives on the in vitro rumen fermentation of silage,the energy metabolism and daily gain of growing cattle were investigated.Experiment 1: Twenty varieties of corn were planted in Yanbei area and used as silage materials,their yield was measured and then the packing silage was made and sampled.The nutritional value,fermentation quality,bacterial community structure and neutral detergent fiber degradability of natural whole plant corn silage of different varieties were analyzed.The results showed that the p H was below 4.20,the ammonia nitrogen content was less than 3% of the total nitrogen,butyric acid was not detected,and the fermentation quality was good for all silages.There were shown differences in bacterial diversity among different varieties of whole plant corn silage.However,Firmicutes,Proteus and Bacteroides were the dominant bacteria on phylum level in these silages.Except for FD189,HF656,JBS963 and YF307(Acetobacter was their dominant bacteria),Lactobacillus and Leuconostoc are the dominant bacteria in silage on genus level.TY18 is the excellent variety for whole plant corn silage production,because of its higher yield,and dry matter degradability(DM-D)and neutral detergent fiber degradability(NDF-D)of silage.Experiment 2:Using the variety TY18 as the silage material,setting without adding lactic acid bacteria(control group,C),adding a single type of lactic acid bacteria(Lactobacillus coryniformis,LCo;Lactobacillus casei,LCa;Lactobacillus pentosus,LPe);Lactobacillus plantarum,LP;Pediococcus acidilactici,PA;Pediococcus pentosaceus,PP;Enterococcus faecium,EF;Streptococcus thermophilus,ST)and added compound lactic acid bacteria(plant milk Bacillus + Pediococcus lactis,LP+PA;Lactobacillus plantarum + Pediococcus lactis +Enterococcus faecium,LP+PA+EF)Set up 11 treatment groups to prepare silage and analyze the fermentation quality,nutritional value and bacterial diversity of silage Based on in vitro rumen fermentation,the effects of adding lactic acid bacteria to silage and adding lactic acid bacteria to the rumen on rumen fermentation parameters,rumen microbial community structure and enzyme activity were compared and analyzed.The results showed that there was no P-values difference in the p H of the silage between the treatments(P>0.05);the lactic acid content of the silage in the lactic acid bacteria treatment group had a tendency to increase,while the water-soluble carbohydrate,starch content and crude protein PA component increased to varying degrees.Lactobacillus bacteria were the dominant bacteria in the silage in each treatment group.Separate addition of various lactic acid bacteria to the silage can increase the abundance of succinobacillus and the activity of carboxymethyl cellulase and xylanase in the rumen.At the same time,the rumen neutral detergent fiber degradation rate(NDF-D)and volatility are increased.The output of fatty acids(VFA)has increased to varying degrees.However,the direct addition of various lactic acid bacteria to the rumen has no P-values effect on rumen fermentation parameters and silage NDF-D.Adding lactic acid bacteria to the silage has a tendency to increase the rumen NDF-D,VFA output,the abundance of fibrobacillus succinate in the rumen and the activity of xylanase.However,the direct addition of lactic acid bacteria to the rumen has no obvious effect.Experiment 3: Fifteen Holstein growing cattles(8-month-old)were divided into 5 groups according to their body weight.Treatments including control group and four lactic acid bacteria adding groups(silage adding and direct feeding compound lactic acid bacteria LP +PA + EF or LP + PA).The experiment included adaptation 10 days and data collection 30 days.The dry matter intake,daily gain,feed nutrient digestibility,rumen fermentation parameters,energy metabolism and blood biochemical indexes were analyzed.The results showed that:the digestibility of EE,NDF and ADF tented to increase,the rumen VFA production,abundance of F.succinogenes and xylanase activity,dry matter intake,digestible energy,net energy,daily gain,blood glucose and insulin content increased significantly(P < 0.05),but feed conversion rate and glucagon content decreased significantly(P < 0.05)for cattles in silage supplemented with compound lactic acid bacteria or direct feeding compound lactic acid bacteria groups compared with those of cattles in control group.In conclusion,adding lactic acid bacteria to whole plant corn did not P-valuesly improve the silage fermentation quality,and Lactobacillus was still the dominant bacteria in silage.However,silage added with lactic acid bacteria could increase neutral detergent fiber degradability and improve the dry matter intake of cattle,so as to improve the production performance of cattle.