Responses of microbial community composition and CAZymes encoding gene enrichment in ensiled Elymus nutans to altitudinal gradients in alpine region.

High-throughput metagenomic sequence technology was employed to evaluate changes in microbial community composition and carbohydrate-active enzymes encoding gene enrichment status in Elymus nutans silages to altitudinal gradients in the world's highest alpine region of Qinghai-Tibetan Plateau (QTP). E. nutans were collected from three different altitudes in QTP: 2,600 m (low altitude), 3600 m (moderate altitude), and 4,600 m [high (H) altitude], and ensiled for 7, 14, 30, and 60 d. Results indicated an improvement in silage quality with the increasing altitude, although the acetic acid concentration and dry matter loss were greater in H altitude silages after 30 d of ensiling. Harmful bacteria or potential pathogens predominated in the microbial community on d 7 and 14 of fermentation, while genera belonging to lactic acid bacteria gradually became the main microorganisms with the increasing altitude on d 30 and 60 of ensiling. The abundance of carbohydrate-active enzymes genes responsible for macromolecular carbohydrate degradation in silage increased with increasing altitude, and those genes were mainly carried by Lactiplantibacillus and Pediococcus at 30 and 60 d of ensiling. The abundance of key enzymatic genes associated with glycolysis and organic acid production in carbohydrate metabolism pathway was higher in H altitude silages, and Lactiplantibacillus and Pediococcus were also the main hosts after 30 d of silage fermentation, except for the fact that acetic acid production was also related to genera Leuconostoc, Latilactobacillus, and Levilactobacillus. IMPORTANCE: The fermentation quality of Elymus nutans silage was getting better with the increase of altitude in the Qinghai-Tibetan Plateau. The abundance of hosts carrying carbohydrate-active enzymes genes and key enzyme genes related to organic acid production increased with increasing altitude during the later stages of fermentation. Lactiplantibacillus and Pediococcus were the core microorganisms responsible for both polysaccharide hydrolysis and silage fermentation in the late stage of ensiling. This study provided insights on the influence of different altitudes on the composition and function of silage microbiome in the Qinghai-Tibetan Plateau, and provided a reference approach for improving the quality and controllability of silage production in high altitude areas of the Qinghai-Tibetan Plateau.

Dry matter content and inoculant alter the metabolome and bacterial community of alfalfa ensiled at high temperature.

Alfalfa silage fermentation quality, metabolome, bacterial interactions, and successions as well as their predicted metabolic pathways were explored under different dry matter contents (DM) and lactic acid bacteria (LAB) inoculations. Silages were prepared from alfalfa with DM contents of 304 (LDM) and 433 (HDM) g/kg fresh weight and inoculated with Lactiplantibacillus plantarum (L. plantarum, LP), Pediococcus pentosaceus (P. pentosaceus, PP), or sterile water (control). The silages were stored at a simulated hot climate condition (35°C) and sampled at 0, 7, 14, 30, and 60 days of fermentation. The results revealed that HDM significantly improved the alfalfa silage quality and altered microbial community composition. The GC-TOF-MS analysis discovered 200 metabolites in both LDM and HDM alfalfa silage, mainly consisting of amino acids, carbohydrates, fatty acids, and alcohols. Compared with LP and control, PP-inoculated silages had increased concentrations of lactic acid (P < 0.05) and essential amino acids (threonine and tryptophan) as well as decreased pH, putrescine content, and amino acid metabolism. However, alfalfa silage inoculated with LP had higher proteolytic activities than control and PP-inoculated silage, as revealed by a higher concentration of ammonia nitrogen (NH3-N), and also upregulated amino acid and energy metabolism. HDM content and P. pentosaceus inoculation significantly altered the composition of alfalfa silage microbiota from 7 to 60 days of ensiling. Conclusively, these results indicated that inoculation with PP exhibited great potential in enhancing the fermentation of silage with LDM and HDM via altering the microbiome and metabolome of the ensiled alfalfa, which could help in understanding and improving the ensiling practices under hot climate conditions. KEY POINTS: • HDM improved fermentation quality and declined putrescine content of alfalfa silage • P. pentosaceus inoculation enhanced the fermentation quality of alfalfa silage • P. pentosaceus is an ideal inoculant for alfalfa silage under high temperature.

Occurrence and fate of antibiotic-resistance genes and their potential hosts in high-moisture alfalfa silage treated with or without formic acid bactericide.

Silage as the main forage for ruminants could be a reservoir for antibiotic resistance genes (ARGs) through which these genes got access into the animals' system causing a latent health risk. This study employed metagenomics and investigated the ARGs' fate and transmission mechanism in high-moisture alfalfa silage treated with formic acid bactericide. The results showed that there were 22 ARGs types, in which multidrug, macrolide-lincosamide-streptogramine, bacitracin, beta-lactam, fosmidomycin, kasugamycin, and polymycin resistance genes were the most prevalent ARGs types in the ensiled alfalfa. The natural ensiling process increased ARGs enrichment. Intriguingly, after 5 days of ensiling, formic acid-treated silage reduced ARGs abundances by inhibiting host bacterial and plasmids. Although formic acid bactericide enhanced the fermentation characteristics of the high-moisture alfalfa by lowering silage pH, butyric acid concentration, dry matter losses and proteolysis, it increased ARGs abundances in alfalfa silage owing to increases in abundances of ARGs carriers and transposase after 90 days of ensiling. Notably, several pathogens like Staphylococcus, Clostridium, and Pseudomonas were inferred as potential ARGs hosts in high-moisture alfalfa silage, and high-moisture alfalfa silage may harbor a portion of the clinical ARGs. Fundamentally, microbes were distinguished as the foremost driving factor of ARGs propagation in ensiling microecosystem. In conclusion, although formic acid bactericide improved the fermentation characteristics of high-moisture alfalfa during ensiling and reduced ARGs enrichment at the initial ensiling stage, it increased ARGs enrichment at the end of ensiling.

Effects of nisin on bacterial community and fermentation profiles, in vitro rumen fermentation, microbiota, and methane emission of alfalfa silage.

BACKGROUND: Alfalfa (Medicago sativa L.) has been used widely in preparing silage. However, forage legumes are prone to contamination by spoilage bacteria during fermentation. Nisin has broad-spectrum antibacterial properties and has been applied as an inhibitor of rumen methane emissions. However, little research has been carried out on the application of nisin in silage. This study therefore aimed to investigate the impacts of different nisin concentrations on the bacterial community and fermentation dynamics, in vitro ruminal fermentation characteristics, microbiota, and methane emissions of alfalfa silage. RESULTS: The detection limits of organic acid in nisin-treated silages were not reached in 0.09 g kg-1 nisin (0.09 level) from days 1 to 7 of ensiling. With increasing nisin concentrations, the silage dry matter increased linearly (P < 0.05), and dry matter loss decreased linearly (P < 0.05). Moreover, both the 0.06 g kg-1 nisin (0.06 level) and 0.09 level treatments increased the relative abundance of Pediococcus acidilactici during ensiling. Concurrently, as the nisin concentrations increased, ruminal methane production decreased linearly (P < 0.05), while the relative abundances of ruminal Succinivibrio, Fibrobacter succinogenes and Ruminobacter amylophilus increased linearly (P < 0.05). The populations of ruminal total bacteria, methanogens, protozoa, and fungi decreased linearly with increasing nisin concentrations (P < 0.05). CONCLUSION: The addition of nisin delayed the fermentation process, preserved more nutrients in alfalfa silage, and promoted fermentation dominated by P. acidilactici in the late phase of ensiling. Moreover, nisin reduced in vitro rumen methane emissions without adverse effects on dry matter digestibility. © 2023 Society of Chemical Industry.

Comprehensive profiling of the metabolome in corn silage inoculated with or without Lactiplantibacillus plantarum using different untargeted metabolomics analyses.

Silage fermentation is a complicated biochemical process involving interactions between microbes and metabolites. However, the overall metabolome feature of ensiled forage and its response to lactic acid bacteria inoculation is poorly understood. Hence, in this study metabolome profiles of whole-plant corn silage inoculated with or without Lactiplantibacillus plantarum were characterised via solid-phase microextraction/gas chromatography/mass spectrometry (SPME-GC-MS), gas chromatography/time-of-flight mass spectrometry (GC-TOF-MS), and Liquid chromatography/Q Exactive HFX mass spectrometry (LC-QE-MS/MS) analysis. There were 2087 identified metabolites including 1143 reliably identified metabolites in fresh and ensiled whole-plant corn. After ensiling, the increased metabolites in whole-plant corn were mainly composed of organic acids, volatile organic compounds (VOC), benzene and substituted derivatives, carboxylic acids and derivatives, fatty acyls, flavonoids, indoles and derivatives, organooxygen compounds (including amines and amides), phenols, pyridines and derivatives, and steroids and steroid derivatives, which includes neurotransmitters and metabolites with aromatic, antioxidant, anti-inflammatory, and antimicrobial activities. Phenylacetaldehyde was the most abundant aromatic metabolite after ensiling. L-isoleucine and oxoproline were the major free amino acids in silage. Ensiling markedly increased the relative abundances of 3-phenyllactic acid, chrysoeriol, 6-O-acetylaustroinulin, acetylcholine, γ-aminobutyric acid, pyridoxine, and alpha-linoleic acid. Inoculation with L. plantarum remarkably changed silage VOC composition, and essential amino acids, 3-phenyllactic acid, and cinnamaldehyde compared with untreated silage. The present study does not only provide a deeper insight into metabolites of the ensiled whole-plant corn but also reveals metabolites with specific biological functions that could be much helpful in screening novel lactic acid bacteria to well ensile forages. Inoculation with L. plantarum significantly affects the metabolome in ensiled whole-plant corn.

Grassland cover declined in Southern Africa but increased in other African subcontinents in early twenty-first century.

The African continent has the most extensive grassland cover in the world, providing valuable ecosystem services. African grasslands, like other continental grasslands, are prone to various anthropogenic disturbances and climate, and require data-driven monitoring for efficient functioning and service delivery. Yet, knowledge of how the African grassland cover has changed in the past years is lacking, especially at the subcontinent level, due to lack of relevant long-term, Africa-wide observations and experiments. In this study, we used Moderate Resolution Imaging Spectroradiometer (MODIS) Land Cover Type (MCD12Q1) data spanning 2001 to 2017 to conduct land use land cover (LULC) change analyses and map grassland distribution in Africa. Specifically, we assessed the changes in grassland cover across and within African subcontinents over three periods (2001-2013, 2013-2017, and 2001-2017). We found that the African grassland cover was 16,777,765.5 km2, 16,999,468.25 km2, and 16,968,304.25 km2 in 2001, 2013, and 2017, respectively. There were net gain (1.32%) and net loss (- 0.19%) during 2001-2013 and 2013-2017 periods, respectively, and the annual rate of change during these periods were 0.11% and - 0.05%, respectively. Generally, the African grassland cover increased by 1.14% (0.07% per annum) over the entire study period (2001-2017) at the expense of forestland, cropland, and built-up areas. The East and West African grassland cover reduced by 0.07% (- 0.02% per annum) and 1.35% (- 0.34% per annum), respectively from 2013 to 2017 but increased in other periods. On the other hand, the grassland cover in North and Central Africa increased throughout the three periods while that of Southern Africa decreased over the three periods. Overall, the net gains in the grassland cover of other African subcontinents offset the loss in Southern Africa and promoted the overall gain across Africa. This study underscores the need for continuous monitoring of African grasslands and the causes of their changes for efficient delivery of ecosystem services.

Physical, fermentative, and nutritional quality of silages made from three Sorghum bicolor varieties as affected by ensiling duration in South-west Nigeria.

Despite large-scale sorghum production in Nigeria, its utilization as livestock feed is limited to the stover following grain harvest. Therefore, we evaluated the physical, fermentative, and nutritive quality of whole-crop silages from three Sorghum bicolor varieties at different ensiling durations. The experiment was 3×5 factorial comprising three varieties (Samsorg14, Samsorg17, and Samsorg41) and five ensiling durations (0, 4, 8, 12, and 16 weeks). Forages were ensiled at the dough stage, and the silos were opened at the pre-determined durations for quality analyses. Samsorg14 silage recorded higher pH (5.88) and significant titratable acidity (8.32 g kg-1), while the least pH was observed for Samsorg17 silage (4.63). The forages ensiled for 8 weeks had a higher pH (5.04) compared with 4.51, 5.03, and 4.57 recorded at 4, 12, and 16 weeks, respectively. In contrast, forages ensiled for 4 weeks recorded the highest titratable acidity (8.39) and Flieg point (104.07). CP content was higher in fresh Samsorg17 (110.64 g kg-1) and lower (71.01 g kg-1) in Samsorg41 ensiled for 8 weeks as influenced by variety × ensiling duration. Cumulative gas volume and methane were higher for Samsorg41 silage (21.21 and 6.76 ml 200 mg-1 DM respectively). Ensiling for 16 weeks resulted in higher silages' IVDMD (44.00%) compared with other ensiling durations. Samsorg14 and Samsorg17 had a relatively stable silage pH, higher CP, and digestibility. Therefore, their silages could be conserved up to 16 weeks to provide high-quality feed for ruminants during the dry season to maintain animal productivity and ultimately enhance food security.

Reducing transmission of high-risk antibiotic resistance genes in whole-crop corn silage through lactic acid bacteria inoculation and increasing ensiling temperature.

The microbial hosts of antibiotic resistance genes (ARGs) found epiphytically on plant materials could grow and flourish during silage fermentation. This study employed metagenomic analysis and elucidated the occurrence and transmission mechanisms of ARGs and their microbial hosts in whole-crop corn silage inoculated with homofermentative strain Lactiplantibacillus plantarum or heterofermentative strain Lentilactobacillus buchneri ensiled under different temperature (20 and 30 °C). The results revealed that the corn silage was dominated by Lactobacillus, Leuconostoc, Lentilactobacillus, and Latilactobacillus. Both the ensiling temperature and inoculation had greatly modified the silage microbiota. However, regardless of the ensiling temperature, L. buchneri had significantly higher ARGs, while it only exhibited significantly higher mobile genetic elements (MGEs) in low temperature treatments. The microbial community of the corn silage hosted highly diverse form of ARGs, which were primarily MacB, RanA, bcrA, msbA, TetA (58), and TetT and mainly corresponded to macrolides and tetracyclines drug classes. Plasmids were identified as the most abundant MGEs with significant correlation with some high-risk ARGs (tetM, TolC, mdtH, and NorA), and their abundances have been reduced by ensiling process. Furthermore, higher temperature and L. buchneri reduced abundances of high-risk ARGs by modifying their hosts and reduced their transmission in the silage. Therefore, ensiling, L. buchneri inoculation and higher storage temperature could improve the biosafety of corn silage.

Heterofermentative Lentilactobacillus buchneri and low dry matter reduce high-risk antibiotic resistance genes in corn silage by regulating pathogens and mobile genetic element.

The study of antibiotic resistance in the silage microbiome has attracted initial attention. However, the influences of lactic acid bacteria inoculants and dry matter (DM) content on antibiotic resistance genes (ARGs) reduction in whole-plant corn silage remain poorly studied. This study accessed the ARGs' risk and transmission mechanism in whole-plant corn silage with different DM levels and treated with Lactiplantibacillus plantarum or Lentilactobacillus buchneri. The macrolide and tetracycline were the main ARGs in corn silage. The dominant species (Lent. buchneri and Lactobacillus acetotolerans) were the main ARGs carriers in whole-plant corn silage. The application of Lent. buchneri increased total ARGs abundance regardless of corn DM. Whole-plant corn silage with 30 % DM reduced the abundances of integrase and plasmid compared with 40 % DM. The correlation and structural equation model analysis demonstrated that bacterial community succession, resulting from changes in DM content, was the primary driving factor influencing the ARGs distribution in whole-plant corn silage. Interestingly, whole-plant corn silage inoculated with Lent. buchneri reduced abundances of high-risk ARGs (mdtG, mepA, tetM, mecA, vatE and tetW) by regulating pathogens (Escherichia coli), mobile genetic elements (MGEs) genes (IS3 and IS1182), and this effect was more pronounced at 30 % DM level. In summary, although whole-plant corn silage inoculated with Lent. buchneri increased the total ARGs abundance at both DM levels, it decreased the abundance of high-risk ARGs by reducing the abundances of the pathogens and MGEs, and this effect was more noticeable at 30 % DM level.

Corrigendum to "Probiotic effect of ferulic acid esterase-producing Lactobacillus plantarum inoculated alfalfa silage on digestion, antioxidant, and immunity status of lactating dairy goats" [Anim Nutr 11 (2022) 38-47].

[This corrects the article DOI: 10.1016/j.aninu.2022.06.010.].

Effects of antioxidant-rich Lactiplantibacillus plantarum inoculated alfalfa silage on rumen fermentation, antioxidant and immunity status, and mammary gland gene expression in dairy goats.

BACKGROUND: Milk synthesis in lactating animals demands high energy metabolism, which results in an increased production of reactive oxygen metabolites (ROM) causing an imbalance between oxidants and antioxidants thereby inducing oxidative stress (OS) on the animals. To mitigate OS and postpartum disorders in dairy goats and gain insight into the impact of dietary choices on redox status during lactation, a feeding trial was conducted using alfalfa silage inoculated with a high-antioxidant strain of Lactiplantibacillus plantarum. METHODS: Twenty-four Guanzhong dairy goats (38.1 ± 1.20 kg) were randomly assigned to two dietary treatments: one containing silage inoculated with L. plantarum MTD/1 (RSMTD-1), and the other containing silage inoculated with high antioxidant activity L. plantarum 24-7 (ES24-7). RESULTS: ES24-7-inoculated silage exhibited better fermentation quality and antioxidant activity compared to RSMTD-1. The ES24-7 diet elevated the total antioxidant capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities in milk, serum, and feces of lactating goats (with the exception of T-AOC in milk). Additionally, the diet containing ES24-7 inoculated silage enhanced casein yield, milk free fatty acid (FFA) content, and vitamin A level in the goats' milk. Furthermore, an increase of immunoglobulin (Ig)A, IgG, IgM, interleukin (IL)-4, and IL-10 concentrations were observed, coupled with a reduction in IL-1ß, IL-2, IL-6, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α concentrations in the serum of lactating goats fed ES24-7. Higher concentrations of total volatile fatty acid (VFA), acetate, and propionate were observed in the rumen fluid of dairy goats fed ES24-7 inoculated silage. Moreover, the diet containing ES24-7 inoculated silage significantly upregulated the expression of nuclear factor erythroid 2 like 2 (NFE2L2), beta-carotene oxygenase 1 (BCO1), SOD1, SOD2, SOD3, GPX2, CAT, glutathione-disulfide reductase (GSR), and heme oxygenase 1 (HMOX1) genes in the mammary gland, while decreased the levels of NADPH oxidase 4 (NOX4), TNF, and interferon gamma (IFNG). CONCLUSIONS: These findings indicated that feeding L. plantarum 24-7 inoculated alfalfa silage not only improved rumen fermentation and milk quality in lactating dairy goats but also boosted their immunity and antioxidant status by modulating the expression of several genes related to antioxidant and inflammation in the mammary gland.

Responses of microbial community dynamics, co-occurrences, functional shifts, and natural fermentation profiles of Elymus nutans silage to altitudinal gradients.

IMPORTANCE: On the Qinghai-Tibet Plateau (QTP), feed shortages are common due to cold environmental conditions and the short growing season of crops. Therefore, effective preservation, such as the ensiling of local forage, is becoming increasingly important to balance the seasonal imbalance between the forage supply and the nutritional needs of domestic animals in this area. However, the structure of the microbial community of the forage, which is influenced by climatic conditions such as altitude differences, has a major impact on the fermentation quality and microbial succession of the ensiled forage. Therefore, we investigated microbial community dynamics, co-occurrence, functional shifts, and natural fermentation profiles of Elymus nutans silage as a function of altitudinal gradients. Results show that silage from Chenduo at higher elevations has better fermentation quality and higher abundance of Lacticaseibacillus and Levilactobacillus than ensiled forage from other regions. This work may contribute to guiding for silage production in QTP.

Effects of bacteriocin-producing Lactiplantibacillus plantarum on bacterial community and fermentation profile of whole-plant corn silage and its in vitro ruminal fermentation, microbiota, and CH4 emissions.

BACKGROUND: Silage is widely used to formulate dairy cattle rations, and the utilization of antibiotics and methane emissions are 2 major problems for a sustainable and environmentally beneficial ruminant production systems. Bacteriocin has received considerable attention because of its potential as an alternative to antibiotics in animal husbandry. However, the impact of bacteriocin-producing lactic acid bacteria on the microbiological conversion process of whole-plant corn silage and rumen fermentation remains limited. The purpose of this study was to assess the effect of 2 class IIa bacteriocin-producing strains Lactiplantibacillus plantarum ATCC14917 and CICC24194 on bacterial community composition and ensiling profiles of whole-plant corn silage and its in vitro rumen fermentation, microbiota, and CH4 emissions. RESULTS: Both bacteriocin-producing strains increased the lactic acid concentration in silage fermented for 7 d, whereas the lowest lactic acid was observed in the ATCC14917 inoculated silage fermented for 90 d (P < 0.05). The highest DM content was observed in the CICC24194 treatment (P < 0.05), and the silages treated with both strains had the lowest DM loss (P < 0.05). Bacteriocin-producing strains promoted the growth of Levilactobacillus brevis on d 60 of ensiling. In addition, treatment with bacteriocin-producing strains increased the in vitro DM digestibility (P < 0.05) and decreased the CH4 production (P < 0.05). The results of random forest and clustering analyses at the genus level showed that ATCC14917 increased the relative abundance of the influential variable Bacillus compared to that in the control group, whereas CICC24194 decreased the relative abundance of the influential variable Ruminococcaceae UCG-005. The CICC24194 treatment had the lowest total bacterial, fungal, protozoan, and methanogen populations (P < 0.05). CONCLUSIONS: Both class IIa bacteriocin-producing L. plantarum strains improved the fermentation quality of whole-plant corn silage by regulating the bacterial community composition during ensiling, with CICC24194 being the most effective. Both bacteriocin-producing strains mitigated CH4 production and improved digestibility by modulating the interactions among rumen bacteria, protozoa, methanogens, and the composition of fibrolytic bacteria.

Metagenomics insights into the effects of lactic acid bacteria inoculation on the biological reduction of antibiotic resistance genes in alfalfa silage.

Antibiotic resistance genes (ARGs) are a new type of pollutant and pose major threats to public health. However, the distribution and transmission risk of ARGs in alfalfa silage as the main forage for ruminants have not been studied. This study first deciphered the effects of Lactobacillus plantarum MTD/1 or Lactobacillus buchneri 40788 inoculations on distribution and transmission mechanism of ARGs in alfalfa silage by metagenomics. Results showed that multidrug and bacitracin resistance genes were the dominant ARGs in ensiled alfalfa. The natural ensiling process increased the abundances of bacitracin, beta_lactam, and aminoglycoside in alfalfa silage with 30% DM, and vancomycin in alfalfa silage with 40% DM. Meanwhile, prolonged wilting increased ARG enrichment in fresh alfalfa. Interestingly, alfalfa silage inoculated with L. plantarum MTD/1 or L. buchneri 40788 reduced the abundances of total ARG, and multidrug, MLS, vancomycin, aminoglycoside, tetracycline, and fosmidomycin resistance genes by reductions of the host bacteria and the enrichment of ARGs located in the plasmid. The hosts of ARG in alfalfa silage were mainly derived from harmful bacteria or pathogens, and some of the clinical ARGs were observed in alfalfa silage. Basically, the combined effect of microbes, MGEs, and fermentation quality was the major driver of ARG transfer and dissemination in microecosystem of ensiling, where the microbes appeared to be the crucial factor. In summary, inoculation with the present lactic acid bacteria could reduce ARG abundance in ensiled alfalfa, and a better effect was observed in L. plantarum-treated silage than in L. buchneri treated silage.

Lignocellulose conversion of ensiled Caragana korshinskii Kom. facilitated by Pediococcus acidilactici and cellulases.

To explore the biofuel production potential of Caragana korshinskii Kom., Pediococcus acidilactici and an exogenous fibrolytic enzyme were employed to investigate the fermentation profile, structural carbohydrates degradation, enzymatic saccharification and the dynamics of bacterial community of C. korshinskii silage. After 60 d of ensiling, all additives increased the fermentation quality. The highest lactic and acetic acids and lowest non-protein nitrogen (NPN) and ammonia nitrogen (NH3 -N) were observed in P. acidilactici and Acremonium cellulase (PA + AC) treated silage. Additionally, all additives significantly increased the ferulic acid content and fibre degradability with the highest values obtained from PA + AC silage. The bacterial community in all silages was dominated by P. acidilactici throughout the entire fermentation process. The bacterial community was also modified by the silage additives exhibiting a relatively simple network of bacterial interaction characterized by a lower bacterial diversity in P. acidilactici (PA) treated silage. The highest 6-phospho-beta-glucosidase abundance was observed in PA-treated silage at the mid-later stage of ensiling. PA treatment exhibited lower structural carbohydrates degradation but performed better in lignocellulose conversion during enzymatic saccharification. These results indicated that pretreating C. korshinskii improved its silage quality and potential use as a lignocellulosic feedstock for the production of bio-product and biofuel.

Effects of inoculating feruloyl esterase-producing Lactiplantibacillus plantarum A1 on ensiling characteristics, in vitro ruminal fermentation and microbiota of alfalfa silage.

BACKGROUND: Ferulic acid esterase (FAE)-secreting Lactiplantibacillus plantarum A1 (Lp A1) is a promising silage inoculant due to the FAE's ability to alter the plant cell wall structure during ensiling, an action that is expected to improve forage digestibility. However, little is known regarding the impacts of Lp A1 on rumen microbiota. Our research assessed the influences of Lp A1 in comparison to a widely adopted commercial inoculant Lp MTD/1 on alfalfa's ensilage, in vitro rumen incubation and microbiota. RESULTS: Samples of fresh and ensiled alfalfa treated with (either Lp A1 or Lp MTD/1) or without additives (as control; CON) and ensiled for 30, 60 and 90 d were used for fermentation quality, in vitro digestibility and batch culture study. Inoculants treated silage had lower (P < 0.001) pH, acetic acid concentration and dry matter (DM) loss, but higher (P = 0.001) lactic acid concentration than the CON during ensiling. Compared to the CON and Lp MTD/1, silage treated with Lp A1 had lower (P < 0.001) aNDF, ADF, ADL, hemicellulose, and cellulose contents and higher (P < 0.001) free ferulic acid concentration. Compared silage treated with Lp MTD/1, silage treated with Lp A1 had significantly (P < 0.01) improved ruminal gas production and digestibility, which were equivalent to those of fresh alfalfa. Real-time PCR analysis indicated that Lp A1 inoculation improved the relative abundances of rumen's total bacteria, fungi, Ruminococcus albus and Ruminococcus flavefaciens, while the relative abundance of methanogens was reduced by Lp MTD/1 compared with CON. Principal component analysis of rumen bacterial 16S rRNA gene amplicons showed a clear distinction between CON and inoculated treatments without noticeable distinction between Lp A1 and Lp MTD/1 treatments. Comparison analysis revealed differences in the relative abundance of some bacteria in different taxa between Lp A1 and Lp MTD/1 treatments. Silage treated with Lp A1 exhibited improved rumen fermentation characteristics due to the inoculant effects on the rumen microbial populations and bacterial community. CONCLUSIONS: Our findings suggest that silage inoculation of the FAE-producing Lp A1 could be effective in improving silage quality and digestibility, and modulating the rumen fermentation to improve feed utilization.

Probiotic effect of ferulic acid esterase-producing Lactobacillus plantarum inoculated alfalfa silage on digestion, antioxidant, and immunity status of lactating dairy goats.

A feeding experiment was conducted to determine the effects of inoculating alfalfa silage with a ferulic acid esterase-producing inoculum on feed digestibility, rumen fermentation, antioxidant, and immunity status of lactating dairy goats. Twenty dairy goats were distributed into 2 experimental groups consisting of control diet (Lp MTD/1, including Lactobacillus plantarum MTD/1 inoculated silage) against diet containing silage treated with ferulic acid esterase-producing L. plantarum A1 (Lp A1). Alfalfa silage inoculated with a ferulic acid esterase-producing Lp A1 had better fermentation quality than the Lp MTD/1 inoculation. The application of Lp A1 improved silage antioxidant capacity as indicated by greater total antioxidant capacity (T-AOC), superoxide dismutase (SOD) and glutathion peroxidase (GSH-Px) activities in Lp A1 treated silage versus Lp MTD/1 treatment. Compared with Lp MTD/1 treated group, inoculation of silage with Lp A1 increased apparent total tract digestibility of dietary dry matter, organic matter and crude protein, and ruminal concentrations of total volatile fatty acids, acetate, propionate and isobutyrate as well. The results of current study also demonstrated improved antioxidant capacity and immune performance of dairy goats with Lp A1 inoculation. Feeding Lp A1-treated silage increased dairy goats' serum antioxidase activity, such as T-AOC, SOD, GSH-Px and catalase, and the serum concentration of immunoglobulin A, while decreased tumor necrosis factor α, interleukin (IL)-2 and IL-6. In addition, compared with Lp MTD/1, diet containing alfalfa silage inoculated with Lp A1 endowed dairy goats' milk with greater fat and protein contents, improved dairy goat milk quality without affecting feed efficiency.