Enzyme additives influence bacterial communities of Medicago sativa silage as determined by Illumina sequencing

Abstract

The goal of the present study was to evaluate the effects of enzymes (cellulase combined with galactosidase) and their combination with Lactobacillus plantarum (LP) on bacterial diversity in alfalfa silages using high-throughput sequencing. Alfalfa forages were treated with or without cellulase + ɑ-galactosidase (CEGA), cellulase + LP (CELP), or ɑ-galactosidase + LP (GALP). After 56 days of ensiling, all treated silages exhibited improved fermentation quality, as reflected by decreased pH, ammonium-N and increased lactic acid levels compared to the control silage (P < 0.05). Enzymatic treatment improved nutrient value by increasing crude protein levels and decreasing neutral detergent fibre (NDF) levels (P < 0.05). Silage treatment significantly altered the bacterial community, as determined by PCoA (P < 0.05). Lactic acid bacteria (LAB) dominated the bacterial community of the treated silage after ensiling. The dominant bacteria changed from Garciella, Enterococcus, Lactobacillus and Pediococcus in the control silage to Lactobacillus and Pediococcus in the CEGA silage and Lactobacillus in the CELP and GALP silages. Collectively, these results suggest that treatment with both enzymes alone and in combination with inoculants greatly increased the abundance of LAB, with Enterococcus, Lactobacillus and Pediococcus observed in the silage treated with enzymes alone (CEGA) and Lactobacillus observed in the silage treated with a combination of enzymes and inoculants (CELP and GALP).

Enhancing the co-ensiling performance of corn stover and cabbage waste via the addition of cellulase

“…Thus, the addition of cellulase could effectively promote the degradation of fiber content, and a higher dosage of cellulase could effectively reduce CL, ADF, and ADL contents. Cellulase can also promote fiber degradation, elevating the WSC production by enzymolysis and acid solubilization, which increases the availability of fermentation substrates for LAB to produce lactic acid Hu et al 2021). The present results were in good agreement with a previous study by Kholif et al (2017), where NDF, ADF, and CL contents were significantly decreased after ensiling.…”

Evaluating the effects of cellulolytic enzymes and Lactobacillus bulgaricus on mycotoxins production and the quality of maize silage

“…In addition, lactic acid production increased when a mixture of enzyme extract and L. bulgaricus was added (Table 3), which demonstrated that the combined enzyme and L. bulgaricus treatment may be more effective compared to the enzyme extract treatment alone; these results were in agreement with a previous study by Li et al (2018). The obtained results were recorded recently in alfalfa silage, since the LAB amplified the enzyme activity, thus accelerating the fermentation process and increasing lactic acid productivity (Hu et al 2021). Further and coming studies is necessary to evaluate the other productivity of enzyme hydrolysis to silage components and its beneficial effects on consumers.…”

“…The addition of extract containing a high amount of enzyme (after 21 d of incubation) to maize silage inoculated with L. bulgaricus increased the growth of L. bulgaricus, as well as increased the dry matter (DM) and organic matter (OM) contents, and the lactic acid production, when compared to the untreated silage or the silage inoculated with only enzymes or L. bulgaricus (Table 3), as well as lowering the pH. Recently, the enhancement of maize silage quality using microbial diversity and rumen degradation proportions were found via the addition of Lactobacillus and cellulase (Hu et al 2021;Zhao et al 2021). According to Khota et al (2017), LAB are incapable of directly decaying lignocellulolytic residues of plants.…”

“…An increase in lactate levels and a reduction in ammonia-N levels were observed by Shepherd and Kung (1996) in silage treated with hydrolytic enzymes, e.g., amylase, cellulase, and pectinase. Recently, a combination of lactic acid bacteria and fibrolytic enzymes, e.g., cellulose and hemicellulose, was applied to improve the nutritional availability of silage (Hu et al 2021). Therefore, more data on maize silage is needed to avoid fungal contamination and mycotoxin production by using safe bacterial inoculants, which represents the aim of this study.…”

Effects of Lactic Acid Bacterial Inoculants on Fermentation Quality, Bacterial Community, and Mycotoxins of Alfalfa Silage under Vacuum or Nonvacuum Treatment

“…The harmful genus Garciella was effectively inhibited by adding either inoculant and NV treatment increased Enterobacter in alfalfa silage, as seen in NV-493 (6.13%), V-493 (0.77%), NV-YX (1.73%), and V-YX (0.51%). To metabolize LA into BA, Garciella can cause protein degradation, NH 3 -N production, and DM loss [27,43]. Enterobacter are also considered undesirable bacteria in silage because they can compete with LAB for available WSC and metabolize LA into AA and other products [3,42].…”