About this Research Topic
Silage is one of the main ingredients in animal diets, and it is an essential source of nutrients, particularly energy and digestible fibre. Unlike properly made and managed silage, poorly shaped or contaminated silage can be a source of undesirable bacteria that may reduce the safety and quality of silage, decrease dairy cow performance, and compromise animal and human health. Some of the unwanted bacteria that are frequently or occasionally associated with silage are Enterobacteria, Listeria, Bacillus spp., Clostridium spp., and Salmonella. Besides, these undesirable microorganisms may be pathogenic or produce toxic metabolic compounds. Therefore, it is critical to prevent the growth of spoilage microorganism in silage, especially under the suboptimal ensiling condition.
For decades, a wide variety of microbial inoculants have been employed to inhibit the growth of harmful microorganism and assist silage preservation. Previously, most of the studies focused on making silage with homofermentative lactic acid bacteria (LAB), as they can produce almost exclusively lactic acid. However, recently there has been a significant increase in the knowledge of new LAB species and strains with the help of culture-independent technique and metabolomics. Because they have the potential ability to directly inhibit Clostridium spp., mitigate the high mycotoxin levels, enhance the silage digestibility and increase aerobic stability, which leads to the better nutritional value of silage. In addition to lactic acid, LAB can synthesize bacteriocins and other broad-spectrum antimicrobial agents such as reuterin, as well as acetoin, and diacetyl. This ability to inhibit the growth of detrimental microorganisms is mediated through several metabolic mechanisms, which mainly depend on the genetic characteristics and substrate in silage. Novel non-LAB species including Propionibacterium and Bacillus species have also been studied as potential silage inoculants. For example, Bacillus subtilis produces a bacteriocin that inhibits yeasts and moulds causing aerobic spoilage of silage. Therefore, it is necessary to intensify the exploration of the function of new microbial inoculants in the process of silage fermentation.
This Research Topic highlights the application of new microbial inoculants to inhibit the growth of harmful organisms during the ensiling process. Submission of Original Research Articles, Reviews, and Mini-Reviews are encouraged on the following topics:
• Exploring the effects of novel microbial inoculants, including LAB, non-LAB or their combination, on inhibiting the growth of harmful organisms in silage.
• The biochemical pathways of novel microbial inoculants that can inhibit detrimental organisms at ensiling fermentation
• The factors/conditions (temperature, moisture, compaction density, harvest time, e.g.) that influence the efficiency of novel microbial inoculants.
Keywords: fermentation quality, Silage, microbial inoculant, lactic acid bacteria, spoilage microorgansim
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