Study On The Effect Of Lactobacillus Plantarum On The Quality Of Corn Silage Based On Different Harvesting Period And Compaction Density

In this experiment,corn silage was harvested at 1/3 milking stage and 2/3milking stage,respectively,and two compaction density levels of 600 kg/m³and 700kg/m³ were experimented.The selected corn silage variety was Dongke 301,which is both grain and feed.Samples were collected on 3d,7d,21d,42d of fermentation to explore the effects of harvest period,compaction density,silage inoculant（Lactobacillus plantarum）and their interaction on corn silage nutrient indicators,fermentation indicators,Microbial diversity and toxins.The results are as follows:Experiment 1:The effect of different concentrations of silage inoculant（Lactobacillus plantarum）in different harvest periods on the quality of whole-plant corn silage.In this experiment,a 2×4 cross-grouping design was used.The whole plant corn was harvested during the 1/3 milking stage and 2/3 milking stage in the same area,and four treatments were carried out on the silage corn in each harvesting period,which adding the silage（Lactobacillus plantarum）with a bacterial count of 0cfu/kg,1×10⁹cfu/kg,1×10¹⁰cfu/kg and 1×10¹¹cfu/kg,3 replicates for each treatment,and the compaction density is 700 kg/m³.The samples were collected and determined the main nutrients（dry matter,crude protein,starch,neutral detergent fiber,acid detergent fiber）and fermentation quality（lactic acid,acetic acid,ammonia nitrogen,p H）in each stage of fermentation（0d,3d,7d,21d,42d）.High-throughput sequencing technology was uesd to analyze the difference of microbial community in each group.Using ELISA detectied to the changes of DON and Aspergillus flavus B1 in the fermentation stage.The results showed that prolonging the silage harvest period significantly increased DM and starch content（p<0.01）,and adding 1×10¹⁰cfu/kg silage inoculant had a tendency to reduce DM and starch loss,and significantly increased the abundance of Lactobacillus（p<0.05）and reduce the diversity of flora in silage.Compared with adding silage inoculant in 2/3 lactation stage,adding silage inoculant in 1/3 milking stage had better fermentation effects,especially the addition of 1×10¹⁰ cfu/kg group significantly reduced the p H and increased the content of lactic acid（p<0.05）.Moreever,the addition of 1×10¹⁰cfu/kg silage inoculant in 2/3lactation stage significantly reduced the concentration of DON.Experiment 2:The effect of different concentrations of silage inoculant（Lactobacillus plantarum）on the quality of whole-plant corn silage under different compaction densities.The experiment used the randomly complete block design with a 2×4 factorial arrangement with different compaction densities（different compaction densities）during the 2/3 milking stage in the same area.Before compacting,the concentration of silage inoculant,experiment treatments and methods were the same as Experiment 1.The results showed that the p H of silage under the high-compacted density condition was significantly lower than that under the low-compacted density（p<0.01）when fermented for 3 days,and the p H of the high-compacted density group was always lower than the low-compacted density during the fermentation period.In addition,the concentration of DON in the high-compacted density group was significantly lower than that in the low-pressure compaction density group（p<0.01）on day 42 of fermentation.And the utilization of different concentrations of silage inoculant showed a tendency that the concentration of DON in the silage decreased.Furthermore,1×10¹⁰ cfu/kg Lactobacillus plantarum significantly increased the abundance of Lactobacillus genus（p<0.05）and decreased the diversity of silage flora.Conclusion:Increasing the compaction density or adding 1×10¹⁰ cfu/kg Lactobacillus plantarum could reduce the loss of dry matter and starch,and promote the accumulation of lactic acid and reduce the concentration of ammonia nitrogen,DON and AFB1 in the silage,and reduced the diversity of bacterial communities in corn silage,and significantly increased the abundance of Lactobacillus,which resulted in inhibiting the growth and reproduction of harmful bacteria.Prolonging the harvest stage of silage corn,could obtain higher dry matter and starch,but the fermentation was not as good as that of early harvest that increased the concentration of DON in the silage.