## 8 Changes in Fermented Silage by LAB  
LABs are mainly responsible for pH reduction and preservation of nutrients in ensiled silages for a long time [11]. Microbiological additives are frequently used in silage fermentation [4; 70]. Microbial inoculum is a mixture of one or more species of microorganisms that should be viable at the time of use. Microbiota in the silages has positive impacts (Figure 4) by decreasing dry matter losses, increasing essential metabolites of interest, inhibiting undesirable microbial growth, and improving nutritional quality [1; 4; 70]. Selecting potent microbes is essential to achieve positive effects. When selecting novel microorganisms, we should focus on specific characteristics of target substrates and general conditions of the ensiling environment to ensure optimal effects [68; 71; 72]. The addition of LAB during the ensiling process improved fermentation quality (higher lactic acid) and maintained the crude protein (CP), acid detergent fiber (ADF), and neutral detergent fiber contents (NDF) [12; 13]. Another report claimed that the addition of LAB significantly increased nutritive profiles of silage at different storage periods [73]. Increased acid detergent lignin [74] and dry matter content (DM) [75] were noted in silages treated with LAB, but the DM level was varied at different storage periods [61]. The organic matter (OM) and DM content were increased in the fresh and rain-treated ryegrass silages treated with LAB [76]. The water-soluble carbohydrate (WSC) level was reduced in the silage treated with LAB [74; 75]; this may be due to LAB being able to utilize WSC and convert into organic acids. The plant metabolites, such as 3-hydroxydecanoic acid, 2-hydroxy-4-methylpentanoic acid, benzoic acid, catechol, hydrocinnamic acid, salicylic acid, 3-phenyllactic acid, 4-hydroxybenzoic acid, (trans, trans)-3,4-dihydroxycyclohexane- 1-carboxylic acid, p-hydrocounaric acid,vanillic acid, azelaic acid, hydroferulic acid, p-coumaric acid, hydrocaffeic acid, ferulic acid, and caffeic acid were increased in grass silages inoculated with LAB [77]. LAB increased \(\alpha\)-tocopherol levels in silages prepared from the mixture of birdsfoot trefoil and timothy, red clover and meadow fescue, or red clover and timothy; whereas, \(\beta\)-carotene levels were either the same or slightly reduced in same silage mixtures [78]; whereas, the silages from rye had higher \(\beta\)-carotene [79].  
The current research practice focuses on homofermatative and heteroreformative lactic acid bacteria. Some non-LAB groups, chemicals, and enzymes are also involved in the silage-making process. Major factors that are important during silage fermentation include aerobic constancy, livestock consumption, and usage. The silage fermentation process involves two major microbes: homofermatative and heterorefermatative species. Homofermatative inoculant groups include _Lactobacillus_, _Pediococcus_, and _Lactococcus_ species. These inoculants can lead to the high productivity of lactic acid, lower the pH, and reduce the breakdown of proteins and sugar molecules in crops. Heterofermatative inoculants include _L. buchneri_ and _L. brevis_. Both species can produce a mixture of lactic acid and acetic acid that can prevent the growth of yeast and mold as contaminants. Recent updates on homofermatative lactic acid bacteria have revealed that they are highly dominant during the fermentation of silage and can lead to the high quality of products. These homofermatative inoculants include _Lactobacillus plantarum_, _Lactobacillus acidophilus_, _P. acididicici_, _P. pentacacacus_, and _Enterococcus fecium_. The growth rate of bacterial inoculum on the dry matter content can increase very rapidly (_Enterococcus_\(\geq\)_pediococcus_\(\geq\)_Lactobacillus_). Most _Pediococcus_ can tolerate higher DM content than _Lactobacillus_ at a wide range of pH values and temperatures [80].