158 Probiotics in silage production

Abstract Probiotics may improve ruminal and/or intestinal conditions and according to FAO/WHO, 2002 which states “mono or mixed strains of living microorganisms which confer desirable health benefits on the host when used adequately”. It should be nonpathogenic, able to give a viable cell count, has a positive effect on the health of the host, and enhance the functions of the intestinal tract. The most commonly used probiotics are from Lentilactobacillus genus formerly quoted as Lactobacillus acidophilus, Lactobacillus lactis, Lactobacillus plantarum, Lactobacillus bulgaricus, Lactobacillus casei, Lactobacillus helveticus, Lactobacillus salivarius, Bifido bacterium spp., Enterococcus faecium, Enterococcus faecalis, Streptococcus thermophilus, Escherichia coli bacteria, and other probiotic fungi such as Saccharomyces cerevisiae and Saccharomyces boulardii. Probiotics may benefit farm animals by improving feed efficiency, body weight gain, milk yield and immune response. In silages, the major claim is regarding the microbiome, coming either from the wild original microbial population endophytic and epiphytic or mainly from silage microbial additives. After silage fermentation, microbiome is largely changed towards less diversity of viable species of bacteria, yeasts and fungi and many different compounds resulted from the substrate undergone through the metabolic pathways. The survival of the original/added microbiome throughout the silage fermentation still remains as a key question and results are largely influenced across trials. Only recently, the use of next-generation sequencing and PacBio single-molecule real-time sequencing technology offered high-throughput and enabled the discovery of a vast majority of microbiota and relative abundances of various microbes in the community to the genus and species precision. The addition of microbial additives during ensiling not only has shown positive effects on silage quality by altering the bacterial community but also changed microbiome and metabolites in the digestive tract of ruminants. Moreover, undisputably metabolites in the rumen were correlated with the bacterial communities. The lactic acid bacteria inoculants in silage production might be beneficial for animal performance and health by influencing the bacterial community and metabolites in the digestive tract of ruminants. Lactic acid bacteria (LAB) may increase intake and digestibility. The positive effects on digestibility are related to degrading feruloyl ester linkages and modifying the matrix structure of forage lignocellulose based on the feruloyl esterase-producing Lactobacillus (Lactiplantibacillus) plantarum. LAB can also act as antimicrobial agents by producing bacteriocins or organic compounds harmful to microbial membranes such as 3-phenyllactic acid. The enhancement of the antioxidant capacity to mitigate oxidative stress in ruminants fed silages was also linked to the free ferulic acid. Some biofunctional metabolites, such as bacteriostatic, antioxidant, anti-inflammatory compounds, and neurotransmitters have been detected in silage too. More precise research tools and targeting the right parameters related to health and metabolism are allowing us to assure the probiotic effects of silages but we still need more deep learning.