Influence of Cellulase or Lactiplantibacillus plantarum on the Ensiling Performance and Bacterial Community in Mixed Silage of Alfalfa and Leymus chinensis

Abstract

The objective of this study was to evaluate the effects of Lactiplantibacillus plantarum or cellulase on the fermentation characteristics and bacterial community of mixed alfalfa (Medicago sativa L., AF) and Leymus chinensis (LC) silage. The harvested alfalfa and Leymus chinensis were cut into 1–2 cm lengths by a crop chopper and they were thoroughly mixed at a ratio of 3/2 (wet weight). The mixtures were treated with no addition (CON), Lactiplantibacillus plantarum (LP, 1 × 106 cfu/g fresh material), cellulase (CE, 7.5 × 102 U/kg fresh material) and their combination (LPCE). The forages were packed into triplicate vacuum-sealed, polyethylene bags per treatment and ensiled for 1, 3, 5, 7 and 30 d at room temperature (17–25 °C). Compared to the CON groups, all the additives increased the lactic acid content and decreased the pH and ammonia nitrogen content over the ensiling period. In comparison to the other groups, higher water-soluble carbohydrate contents were discovered in the CE-inoculated silages. Compared to the CON groups, the treatment with LPCE retained the crude protein content and reduced the acid detergent fiber content. The principal coordinate analysis based on the unweighted UniFrac distance showed that individuals in the AF, LC, CON and LPCE treatment could be significantly separated from each other. At the genus level, the bacterial community in the mixed silage involves a shift from Cyanobacteria_unclassified to Lactobacillus. Lactobacillus dominated in all the treatments until the end of the silage, but when added with Lactiplantibacillus plantarum, it was more effective in inhibiting undesirable microorganisms, such as Enterobacter, while reducing microbial diversity. By changing the bacterial community structure after applying Lactiplantibacillus plantarum and cellulase, the mixed silages quality could be further improved. During ensiling, the metabolism of the nucleotide and carbohydrate were enhanced whereas the metabolism of the amino acid, energy, cofactors and vitamins were hindered. In conclusion, the relative abundance of Lactobacillus in the mixed silage increased with the addition of Lactiplantibacillus plantarum and cellulase, which also improved the fermentation quality.

The effect of fermented natural lactic acid bacteria liquid and water-soluble carbohydrate admixture on alfalfa (Medicago sativa L.) silage fermentation quality, in vitro digestibility and methane production

“…In our study, the total yeast count of the alfalfa plant was determined as Log10 5.66 cfu/g and the mold count as Log10 4.04 cfu/g. These yeast values are higher than the values reported by Wang et al (2023) and Si et al (2023) in their studies, while the mold value of Wang et al (2023) is lower than our study. The yeast and mold count of Silva et al (2020) in alfalfa plants are similar to our study.…”

“…When the data was analyzed, the LAB count of the fresh alfalfa plant was determined as Log10 4.38 cfu/g. This value was higher than the value reported by Sun and Yang (2021), lower than the value reported by Silva et al (2020), and Wang et al (2023), and similar to the value reported by Si et al (2023). A meta-analysis by Oliveira et al (2017) : Values with different letters in the same column were found to be different (P<0.05); NH 3 -N/TN: Ammonia nitrogen, CO 2 : Carbondioxide g/kg DM, LA: Lactic acid g/kg DM, AA: Acetic acid g/kg DM, PAYMV: Post aerobic yeastmold values.…”

Effects of lactic acid bacteria inoculants on the nutrient composition, fermentation quality, and microbial diversity of whole-plant soybean-corn mixed silage

“…Ensiling systems require low pH for feed preservation and inhibiting harmful microorganisms and molds ( Zhang et al, 2022 ). This study aligns with Si et al (2023) , demonstrating an initial rapid pH drop in early silage fermentation, continuing as fermentation progressed. The control silage’s pH (4.03) at 56 days was slightly lower than the pH (4.44) reported by Kizilsimsek et al (2017) for 60-day corn and soybean silage, likely due to higher WSC content in the whole-plant corn silage.…”

“…Lactobacillus plantarum is a homofermentative LAB favored in silage production, metabolizing WSC in silage to lactic acid and rapidly lowering pH to inhibit yeast and mold growth ( Mu et al, 2020 ). Inoculation with L. plantarum in mixed alfalfa and Leymus chinensis silage improves fermentation quality by increasing LA content and reducing pH and NH 3 -N content ( Si et al, 2023 ). In contrast, L. buchneri , a heterofermentative LAB, enhances silage’s aerobic stability by converting LA into acetic acid (AA), thereby inhibiting filamentous fungi growth ( Yin et al, 2023 ).…”

Lactic Acid Bacteria and Cellulase Improve the Fermentation Characteristics, Aerobic Stability and Rumen Degradation of Mixed Silage Prepared with Amaranth and Rice Straw

“…The reason for this result may be associated with the reduction in effluent production by lactobacillus action that includes approximately 8% DM [26]. In addition, supplementation of L. plantarum is beneficial for the homo-fermentation of silage and can inhibit decomposition in organic substances induced by inadequate production of lactic acid [27], which are conducive to decreasing the nutritional loss. WSC is an important fermentation substrate for lactic acid bacteria.…”