Effect of Enterococcus faecium and Bacillus subtilis strains on the microbiota and nutritional value of grass-legume silage

   Ensiling is a feed preservation process the quality of which is largely determined by microbiological processes. Under unfavorable harvesting conditions, high initial moisture content of the plant material, or non-compliance with technology, undesirable microorganisms such as enterobacteria, clostridia, and other species may proliferate instead of lactic acid bacteria. This proliferation degrades the nutritional value and quality of the finished feed.

   The aim of the present study was to investigate the effect of new strains of Enterococcus faecium and Bacillus subtilis, employed as biopreservatives, on the microbiota and nutritional value of grass-legume silage.

   The experiment evaluated the inoculation of ensiled biomass with Enterococcus faecium 46 and a combination of Enterococcus faecium 46 and Bacillus subtilis 18, in comparison to a control treatment without a preservative. Silage nutritional parameters and microbiota composition were determined on the 30^th day of plant mass fermentation. The most favorable results regarding dry matter content, neutral detergent fiber, and the proportion of lactic acid in total organic acids were observed with the combined application of Enterococcus faecium and Bacillus subtilis strains. Microbiota assessment via quantitative PCR in this experimental variant revealed the highest abundance of Lactobacillus species and a reduced count of Enterobacteriaceae family representatives, including Escherichia coli, Klebsiella sp., and Citrobacter sp. These findings suggest that the synergistic action of these strains during feed preservation effectively inhibited the development of putrefactive and pathogenic toxin-forming bacteria due to enhanced lactic acid synthesis. Based on these results, we conclude that this bacterial complex holds significant promise for improving fermentation and nutrient preservation in ensiled forages.

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