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.

In this study, the triterpenoids in the leaves of Lactuca indica L.cv. Mengzao (LIM) were extracted via microwave-assisted ethanol extraction, and the optimum extraction conditions for triterpenoids were determined through single-factor experiments and the Box–Behnken method. The effects of three factors (solid–liquid ratio, microwave power and extraction time) on the total triterpenoids content (TTC) were evaluated. The TTC of different parts (roots, stems, leaves and flowers) of LIM in different growth stages was studied, and the scavenging effects of the highest TTC parts on DPPH, ABTS and hydroxyl free radicals were investigated. The results showed that the optimum extraction conditions for microwave-assisted extraction of total triterpenoids from LIM leaves were as follows: solid–liquid ratio of 1:20 g/mL; microwave power of 400 W; and extraction time of 60 min. Under these conditions, the TTC was 29.17 mg/g. Compared with the fresh raw materials, the TTC of the materials increased after freeze drying. The leaves of LIM had the highest TTC, and the flowering stage was the best time. The triterpenoids from the leaves had a strong ability to eliminate DPPH and ABTS free radicals, and the elimination effect of dried leaves was better than that of fresh leaves, while the elimination effect of hydroxyl free radicals was not obvious. The tested method was used to extract total triterpenoids from LIM using a simple process at low cost, which provides a reference for developing intensive processing methods for L. indica.

During aerobic exposure of silage, the fatty acid and amino acid composition may alter the quality and palatability, resulting in economic losses in livestock production. The objective of this study was to evaluate the effects of Lactiplantibacillus plantarum (LP), Lenti Lentilactobacillus buchneri (LB), and a mixture of LP and LB (PB) on the fatty acids, amino acids, and antioxidant capacity of Leymus chinensis silage during aerobic exposure. The lactic acid bacteria were added at 1 × 106 CFU/g. The silage treatments were opened after 60 days of fermentation, and sampled on days 0, 4, and 8 of aerobic exposure. The LB group had higher total fatty acid and polyunsaturated fatty acid content, and less decrease in amino acid content and antioxidant capacity, while the LP group had a higher monounsaturated fatty acid content but a larger decrease in all indicators after exposure. Correlation analysis showed that Lactobacillus, Cryptococcus, Penicillium, and Thermoascus were more correlated with fatty acid changes, and that Lactobacillus, Actinomyces, Clostridium, and Penicillium were more correlated with amino acid changes. In conclusion, Lentilactobacillus buchneri could effectively improve the antioxidant capacity and fatty acid and amino acid contents of Leymus chinensis silage during aerobic exposure, while Lactiplantibacillus plantarum could effectively improve the content of each index of Leymus chinensis silage at opening, but deterioration was faster during aerobic exposure.