Silage Fermentation Research Articles

Effect of mixing paddy straw with molasses and urea on fermentation characteristics and nutritive value of maize silage

The present investigation was aimed at studying the improvement of fermentation and nutritive quality of rice straw-maize silage by the inclusion of different additives. In the experiment, paddy straw and green maize fodder were mixed in ratios of 100:0, 75:25, 50:50, 25:75, and 0:100 for silage preparation. These combinations were made in a triplicate and added with no additive (C), 2% urea (T1), 1% molasses (T2) and a mixture of 2% urea and 1% molasses (T3) in completely randomized design (CRD). The silages were harvested after 45 days and then analyzed for chemical composition, fermentation characteristics and anti-nutritional factors. Results revealed that dry matter (DM), acid detergent fibre (ADF), neutral detergent fibre (NDF), crude fibre (CF), ash and pH increased with an increase in the proportion of paddy straw in all combinations. Addition of 2% urea increased in vitro dry matter digestibility (IVDMD), crude protein (CP) and total gas production (TGP) of paddy straw and maize fodder silage. Urea treatment considerably reduced the oxalate content and increased the tannin content of paddy straw and maize fodder silage. In the present study, silage prepared by combining paddy straw and maize fodder in ratio of 25:75 had good aroma and fermentation characteristics which can be, therefore, utilized for effective silage making.

Hazardous risk of antibiotic resistance genes: Host occurrence, distribution, mobility and vertical transmission from different environments to corn silage

Antibiotic resistance genes (ARGs) are one of the emerging contaminants posing a great deal of hazardous risk to public health. This study employed metagenomics and deciphered the potential risk of the antibiotic resistome and their vertical transfer to ensiled whole-crop corn silage harvested from six climate zones: 1. Warm temperate-fully humid-hot summer (Cfa), 2. Arid-desert-cold arid (BWk), 3. Snow-desert-cold summer (Dwc), 4. Snow-desert-hot summer (Dwa), 5. Arid-steppe-cold arid (BSk), and 6. Equatorial-desert (Aw) based on the Köppen-Geiger climate classification in China. The findings demonstrate a high diversity of ARGs, which is related to the drug classes of tetracycline, ciprofloxacin, lincosamide, fosfomycin, and beta lactam. Resistome variations are mostly related to variations in microbial composition and fermentation characteristics of the silages from different climate zones, which are indirectly influenced by environmental conditions. The most dominating ARGs in corn silage were tetM, acrA, H-NS, lnuA, emrR, and KpnG, which is primarily hosted by Klebsiella and Lactobacilli. There were 5 high-risk ARGs (tetM, bacA, SHV-1, dfrA17, and QnrS1) in silage from different climate zones, and the tetM was the most prevalent high-risk ARG. However, throughout the ensiling process, the abundance of ARGs, and mobile ARGs were reduced. The resistome contamination in silage from Tibet (Dwc) with high altitude and harsh environment was relatively low due to the low variety and abundance of ARGs, the low abundance of mobile ARGs and high-risk ARGs. In addition, most of the bacteria responsible for the silage fermentation were also found to be the hosts to the ARGs, although their abundance decreased after 90 d of silage fermentation. Hence, we alert the existence of ARGs-related biosafety risk in silages and call for more attention to the silage ARGs, their hosts, and mobile genetic elements in order to curtail their possible risk to public health.

The Effect of Oregano (Origanum onites) Pulp to Quality Parameters of Meadow Silage

It was aimed to determine the effect of ensiling by adding Oregano pulp at different rates to the meadow grass on the physical quality properties of silages, silage fermentation and aerobic stability. In the study, dry oregano pulp at the rate of 3% (OP3) to 5% (OP5) by weight basis and without additives (control) was added to the first harvested of meadow grass in 2021 and it was ensiled as 3 groups. A total of 18 silage samples, 6 for each group, were left for fermentation in 1 liter glass jars for 60 days. Addition of oregano pulp in two different ratios decreased the DM content of silages compared to the control group (p<0.05). Control and silage groups with added oregano pulp were obtained in 2nd and 3rd roughage quality class, and their relative feed values were between 101.06 and 106.55. As a result of the physical properties of the silages, silages without additives were obtained as "satisfactory", while "good" quality silages were obtained from the groups with 3% and 5% oregano pulp. pH levels of silages were obtained between 4.37-4.89. The LA concentrates of the silage decreased significantly with the addition of oregano pulp, while the AA and BA levels of the silages were also decreased (p<0.001). As the ratio of oregano pulp increased from 3% to 5%, it was observed that the aerobic stability of the silages increased compared to the control group. As a result, it was concluded that oregano pulp can be evaluated as a silage additive.

Metagenomic characterization of the cecal microbiota community and functions in finishing pigs fed fermented Boehmeria nivea.

Ramie (Boehmeria nivea, BN) is used as livestock forage through suitable silage fermentation owing to its nutritional value. To date, relatively few studies have investigated the effects of dietary fermented BN (FBN) on gut health in finishing pigs. The aim of the present study was to investigate the effects of dietary supplementation with 20% FBN on intestinal morphology, gene expression, and the functional response of the gut microbiota in finishing pigs. We found that FBN did not significantly affect serum antioxidant enzyme activities, ileal morphology, or the expression of genes encoding antioxidant enzymes, inflammatory cytokines, or tight junction proteins in the liver of the pigs. However, the gene expression levels of aryl hydrocarbon receptor (AHR) and interleukin 6 (IL6) were significantly downregulated in the ileum. A metagenomic analysis demonstrated that, compared with that seen in the control group, the cecal microbiota of pigs in the FBN treatment group was more closely clustered and contained a greater number of unique microbes. Bacteria were the predominant kingdom in the cecal microbiota, while Firmicutes, Bacteroidetes, and Proteobacteria were the dominant phyla, and Streptococcus, Lactobacillus, and Prevotella were the dominant genera. Dietary FBN significantly increased the abundance of the probiotic bacterium Roseburia inulinivorans (p < 0.05). Functional analysis of the cecal microbiota showed that ABC transporter levels and glycolysis/gluconeogenesis-associated functions were diminished in FBN-fed pigs. Meanwhile, CAZyme analysis revealed that dietary FBN significantly downregulated the contents of carbohydrate-active enzymes, such as GT2, GH1, GH25, and GH13_31. In addition, cytochrome P450 analysis revealed that the abundance of CYP51 and CYP512 decreased with FBN treatment. An assessment of antibiotic resistance based on the Comprehensive Antibiotic Resistance Database (CARD) annotation indicated that the cecal microbes from pigs in the FBN treatment group had increased resistance to lincosamide, streptogramin, and chloramphenicol and reduced resistance to amikacin, isepamicin, neomycin, lividomycin, gentamicin, paromomycin, ribostamycin, and butirosin. Finally, virulence factor-related analysis showed that putative hemolysin-associated functions were decreased, whereas fibronectin-binding protein, flagella, and alginate-associated functions were increased. Taken together, our data showed that FBN supplementation exerted only minor effects on intestinal morphology and microbial community composition, suggesting that it is potentially safe for use as a supplement in the diets of finishing pigs. However, more studies are needed to validate its functionality.

Evaluation of the fermentation performance and functional properties of bacterial communities of amaranth silage supplemented with Limosilactobacillus fermentum and Latilactobacillus graminis

BackgroundThe objective was to determine the effects of different lactic acid bacteria (LAB) on amaranth (Amaranthus hypochondriaus) silage fermentation characteristics, changes in bacterial communities and their functional properties, and to investigate the preferential effects and mechanisms of action of Limosilactobacillus fermentum (L. fermentum) and Latilactobacillus graminis (L. graminis) on the bacterial communities of silage. LAB were screened and identified from native grasses and its naturally fermented silage, and their effects on fermentation performance and bacterial community of amaranth after 60 days of fermentation were investigated. BL1 and BL5 strains were identified as L. fermentum and L. graminis, respectively. They could grow normally at concentrations of 3.0% and 6.5% NaCl, tolerating pH and temperature ranges of 3.5 –9.0 and 4.0 – 9.0, 30 – 45 ℃ and 10 – 45 ℃, respectively. The distilled water, Lactiplantibacillus plantarum (commercial inoculant), L. fermentum, and L. graminis were inoculated into amaranth at a total of 1 × 105 cfu/g fresh material and labeled AhSCK, AhSLP, AhSLF, and AhSLG, respectively, while the fresh amaranth was labeled YLS.ResultsAs expected, the water soluble carbohydrates of AhSCK was lower than AhSLG (p < 0.05). The highest number of LAB was found in AhSLF (p < 0.05). The lactic acid (LA) content of AhSLP was significantly higher (p < 0.05) than other silage. Nevertheless, acetic acid (AA) content of AhSLF was significantly different from other silage (p < 0.05). All the amaranth silage was well preserved with low pH (4.16 – 4.51) and acceptable levels of butyric acid (0.00 – 0.86%FM). At the species level, Pantoea agglomerans, Pseudomonas oryzihabitans, and Cenchrus americanus served as the dominant strains in fresh amaranth, with relative abundances lower than 1% after ensiling.. Lentilactobacillus buchneri, Levilactobacillus brevis, and L. fermentum were the dominant strains of AhSCK, AhSLP and AhSLF. Nevertheless, the predominant strains of AhSLG was Xanthomonas oryzae. Both fresh material and silage, L. fermentum, L. plantarum, Levilactobacillus brevis, Pantoea agglomerans, Pseudomonas oryzihabitans, Cenchrus americanus, Pseudomonas coleopterorum, Priestia aryabhattai, and Exiguobacterium sibiricum were significantly different in relative abundance (p < 0.01).Functional prediction analysis showed that in pyruvate metabolism, glycolysis/gluconeogenesis and amino sugar and nucleotide sugar metabolism were enriched after ensiling. AhSLF showed the most obvious trend of increasing abundance of pentose phosphate pathway, biosynthesis of secondary metabolites and biosynthesis of antibiotics, while the abundance of metabolic pathways decreased significantly (p < 0.05).ConclusionsL. fermentum can be recommended as an additive to improve the quality of amaranth silage, as it regulates the epiphytic microbiota in silage, improving the fermentation quality and metabolic capacity of the bacterial community.Graphical

Silage preparation and sustainable livestock production of natural woody plant.

As the global population increases and the economy grows rapidly, the demand for livestock products such as meat, egg and milk continue to increase. The shortage of feed in livestock production is a worldwide problem restricting the development of the animal industry. Natural woody plants are widely distributed and have a huge biomass yield. The fresh leaves and branches of some woody plants are rich in nutrients such as proteins, amino acids, vitamins and minerals and can be used to produce storage feed such as silage for livestock. Therefore, the development and utilization of natural woody plants for clean fermented feed is important for the sustainable production of livestock product. This paper presents a comprehensive review of the research progress, current status and development prospects of forageable natural woody plant feed resources. The nutritional composition and uses of natural woody plants, the main factors affecting the fermentation of woody plant silage and the interaction mechanism between microbial co-occurrence network and secondary metabolite are reviewed. Various preparation technologies for clean fermentation of woody plant silage were summarized comprehensively, which provided a sustainable production mode for improving the production efficiency of livestock and producing high-quality livestock product. Therefore, woody plants play an increasingly important role as a potential natural feed resource in alleviating feed shortage and promoting sustainable development of livestock product.

Epiphytic microbiota in Swedish grass-clover herbage and the effect of silage additives on fermentation profiles and bacterial community compositions of the resulting silages.

To investigate the epiphytic microbiota in grass-clover herbage harvested at different sites and occasions; and to explore the effect of different silage additives on the resulting silage microbiota. Herbage was harvested from grass-clover leys at geographically distributed sites in a long-term field experiment in Sweden, in early and late season of two consecutive years. Different silages were made from the herbage using; 1) no additive, 2) acid-treatment, and 3) inoculation by starter culture. Herbages were analyzed for botanical and chemical composition, and the resulting silages for products of fermentation. Bacterial DNA was extracted from herbage and silage samples, followed by sequencing using Illumina 16S rRNA amplicon sequencing. Herbage microbiota showed no clear correlation to site or harvesting time. Silage additives had a major effect on the ensiling process; inoculation resulted in well fermented silages comprising a homogenous microbiota dominated by the genera Lactobacillus and Pediococcus. A minor effect of harvest time was also observed, with generally a more diverse microbiota in second harvest silages. Untreated silages showed a higher relative abundance from non-lactic acid bacteria compared to acid treated silages. In most silages, only a few bacterial amplicon sequence variants contributed to most of the relative abundance. The epiphytic microbiota in grass-clover herbage were found to be random and not dependent on site. From a microbial point of view, the most predictable and preferable silage outcome was obtained by inoculation with a starter culture. Acid-treatment with formic- and propionic acid surprisingly resulted in a less preferable silage. Silage making without additives cannot be recommended based on our results.

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

ABSTRACTSilage 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.

Fermentation Properties and Nutritive Value of Sunflower Ensiled With Different Mixing Ratios of Silage Maize, Sweet Corn and Sweet Sorghum

In recent years, with the effect of global warming, researches on the potential of plants that are more resistant to drought as forage crops and their ensiling properties have become increasingly widespread. Current study aimed to investigate the ability of ensiling, fermentation quality and nutritive value of a sunflower variety, which is more drought resistant than many forage crops, with silage corn, sweet corn and sweet sorghum at different mixing ratios. Plant species used as silage material in present study were grown simultaneously in separate plots. All plants were harvested by hand in the range of about 25-32% dry matter and these harvested crops were theoretically chopped with 2-3 cm electric shredding machine for silage. In addition to pure silages of all crop materials, mixed silages of 25%+75%, 50%+50% and 75%+25% were made in 3 replications. Besides some properties of silage beginning materials, some fermentation properties and feed quality parameters of resulted silages were investigated. As a result of this study, 50%+50% mixed silage of the sunflower variety used as silage material with maize, sweet corn and sweet sorghum increased the silage fermentation quality compared to the pure sunflower silages and improved the silage feed quality compared to the pure cereal (corn, sweet corn and sweet sorghum) silages.

Compaction, aeration and addition of mycotoxin contaminated silage alters the fermentation profile, mycotoxin content and aerobic stability of ryegrass (Lolium perenne) silage

This study investigated the effect of compaction, aeration and addition of a naturally mycotoxin contaminated ryegrass silage (MCS) containing 1803 µg/kg DM penicillic acid, on the nutritional value and mycotoxin content after ensiling and subsequent aerobic stability of ryegrass Lolium perenne silage (second-cut, June 2020, UK). Mini silos (30 L) were filled with differential compaction (500 kg FW/m3 and 333 kg FW/m3), aeration by injection of air (1L per 48h for 30d then 1L per 7d) and addition of MCS (1.5 g/kg FW ensiled forage) in a 2×2×2 factorial design. During ensilage, mean CO2% (kg FW) in the aerated silos increased with low compaction. Crude protein (CP) increased and ash decreased with aeration. Mean silage fermentation end products acetic (AA), lactic (LA) and propionic acid (PA) concentrations increased with MCS. PA concentration increased with aeration/low compaction. LA decreased and ethanol increased with low compaction. Mycotoxin profiles differed between the silages on opening and after 14-days incubation in aerobic conditions with disappearance of fusarenon X and penicillic acid and appearance of mycophenolic acid and roquefortine C (318 µg/kg DM and 890 µg/kg DM). Addition of MCS, increased the concentration of penicillic acid on opening with an interaction with aeration (80.6µg/kg DM MCS × aerated, 40.0 µg/kg DM in the MCS × sealed). Aerobic stability was affected by aeration and low compaction with reduced time taken to heat to +5°C and +10°C above ambient temperature, higher rate of increase in pH and higher cumulative temperatures to the first peak temperature. Higher mycotoxin concentration at opening had a similar effect increasing time to heat +5°C and +10°C above ambient temperatures in aerobic conditions. Regression analysis showed predominantly direct relationships between silage fermentation end-product concentrations and aerobic stability. This study revealed interactions between silage bacteria and fungi activity from the concentrations of fermentation end-products and mycotoxins during ensilage and subsequent aerobic spoilage. The results supported current best practice for silage making, promoting conditions for improved preservation and aerobic stability. The addition of MCS had unexpected positive effects. However, factors associated with the MCS benefiting aerobic stability were not determined.

Effects of inoculation of corn silage with Saccharomyces cerevisiae on silage fermentation characteristics, nutrient digestibility, mycoflora and aflatoxin production

In the present study, fresh whole corn plants along with half milk kernels line were treated with live and hydrolysed yeast with different concentrations before ensiling and kept in airtight bags and then into mini silos in order to achieve anaerobic conditions for proper fermentation. The buckets were opened after different time intervals to characterise the material, quick acidification, dry matter recovery, and aerobic stability of silage respectively. Moreover, mycoflora and aflatoxin contamination were also analysed. The overall result reported that the silage quality was improved by the application of live and hydrolysed yeast. The best result was reported by the application of live yeast (T2: 10 g/kg) which significantly improved the fermentative, proximate, and digestibility parameters and reduced the mycoflora and aflatoxin contamination. Our results present promising new options for the use of natural compounds that may help to improve silage quality and reduce aflatoxin contamination.

In Vitro Rumen Fermentation Characteristics, Estimated Utilizable Crude Protein and Metabolizable Energy Values of Grass Silages, Concentrate Feeds and Their Mixtures.

Four formulations of concentrate feeds, three contrasting qualities of grass silages, and mixtures of the silages (55%) and concentrates (45%, dry weight) were tested for in vitro fermentation kinetics, in vitro dry matter degradation (IVDMD), utilizable crude protein (uCP), and metabolizable energy (ME) values. The concentrates were pelleted control concentrate for dairy cows (CONT-P); pelleted alkaline concentrate with ammoniated cereal grains (ALKA-P); mash form concentrate with ALKA-P main ingredients but with feed-grade urea and barley replacing ammoniated cereal grain (UREA-M); and mash form of ALKA-P ingredients prior to alkalization (ALKA-M). The grass silages were early cut, late cut, and a mixture (1:1) of early and late cut. The objectives were to test if the feeds differed in the tested parameters within each feed category and assess the modulatory effect of concentrate feeds on the grass silage fermentation characteristics in the mixed diets. No interaction effects of the concentrate feeds by silage quality were observed for the tested parameters in the mixed diets. For concentrates, the pelleted diets were higher (p < 0.05) in IVDMD and molar proportion of propionate but lower in butyrate. The ALKA-P produced the highest estimated uCP (p < 0.01). For silages, uCP, ME, total short-chain fatty acids (VFAs), and molar proportions of propionate and branched-chain VFAs decreased (p < 0.05) with increasing stage of maturity. In conclusion, the ALKA-P could match the CONT-P in uCP and ME values and fermentation characteristics. Results for silages and their mixtures with concentrates highlight the importance of silage quality in dietary energy and protein supply for ruminants.

Autumn grass treated with a hydrolysable tannin extract versus lactic acid bacteria inoculant: Effects on silage fermentation characteristics and nutritional value and on performance of lactating dairy cows.

Hydrolysable tannins (HT) show potential as silage additive for autumn herbage silages, high in (rumen degradable) protein, as they may reduce proteolysis.Additionally, they have abilities to form pH-reversible tannin-protein complexes, non-degradable in the rumen but degradable in theabomasum and intestines of ruminants. Therefore they can improve milk N efficiency and shift N excretions from urine to faeces, possibly mitigating the environmental impact of ruminants. In this study, two small bunker silos were filled with autumn grass. One was treated with 20 g/kg DM HT extract (TAN) (TannoSan-L), the other with 8 mg/kg DM inoculant containing lactic acid bacteria (INO) (Bonsilage Fit G). Secondly, micro-silos (2.75 L) were filled with four treatments; (1) grass without additive (CON) (n = 5); (2) TAN (n = 5); (3) INO (n = 5); and (4) TAN + INO (n = 5). The bunker silos were used in a cross-over feeding experiment with periods of 4 weeks involving 22 lactating Holstein cows (average ± SD: 183 ± 36.3 days in milk, 665 ± 71.0 kg body weight, and 33.8 ± 3.91 kg/day milk yield). The HT dose was insufficient to reduce proteolysis or alter chemical composition and nutritional value in the micro- and bunker silages. Including grass silage added with TAN (3.2 g HT/kg DM) in the diet, did not affect feed intake nor fat and protein corrected milk yield in comparison to feeding the grass silage added with INO in a similar diet. The TAN-fed cows had an increased faecal N excretion and decreased apparent total-tract N and organic matter digestibility, but no improvement in the cows' N utilization could be confirmed in milk and blood urea levels. Overall, feeding an autumn grass silage treated with 20 g/kg chestnut HT extract did not affect the performance of dairy cows in comparison to feeding an autumn grass silage treated with a lactic acid bacteria inoculant.

Compacted Silage Fermentation on Whole Sweet Sorghum Plant for Distributed Bioethanol Production

Compacted Silage Fermentation on Whole Sweet Sorghum Plant for Distributed Bioethanol Production

Sustainable Use of Pennisetum sinese: Effect on Nutritional Components and Fermentation Quality of Stylosanthes guianensis in Tropics

Mixed ensiling of Stylosanthes guianensis and Pennisetum sinese is an alternative method to improve the nutrient composition of feeds for healthy and green ruminant production in the tropics. This study examined the fermentation quality, nutritional composition, and microbial population in silage to select the most suitable ratio of mixed silage containing different proportions of S. guianensis and P. sinese. It was completely randomized and consisted of four treatments with five replications based on fresh weight as follows: S0, 100% P. sinese; S15, 85% P. sinese + 15% S. guianensis; S30, 70% P. sinese + 30% S. guianensis; and S45, 55% P. sinese + 45% S. guianensis. The silage samples were opened and detected after ensiling for 30 days. The results showed that the content of dry matter and crude protein in mixed silage increased with the increase in S. guianensis, while the content of acid detergent fiber decreased significantly, and the maximum or minimum value appeared in the S45 group. As the proportion of S. guianensis increased, the pH, ammonia nitrogen, and acetic acid in mixed silage gradually increased, but the lactic acid content decreased. In addition, the content of lactic acid bacteria and yeast showed a significant downward trend. Further study showed that there was a complex correlation between nutrient compositions, fermentation characteristics, and microbial numbers in mixed silage, especially dry matter, crude protein, and lactic acid bacteria. From the sensory evaluation of silage, S30 was excellent and exhibited an aromatic smell, a hazel color, and the loosest texture. However, from the results of the proportion of organic acids in mixed silage fermentation and further principal component analysis, the highest comprehensive score was in the S15 group. Considering the nutritional compositions and fermentation quality, the optimum ratio of mixed fermentation between S. guianensis and P. sinese in this experiment was 30:70.

Ensilibility and protein degradation characteristics of forage from mountain grasslands containing tanniferous species

AbstractEnsiling forage from species‐rich mountain grasslands is challenging. Low concentrations of fermentable carbohydrates and the coarse morphological structure of the forage promote the activity of butyric acid forming bacteria. This is associated with the formation of ammonia from protein degradation, resulting in an insufficient pH decline. On the other hand, forage from species‐rich swards may contain tanniferous plant species which contain varying contents of condensed tannins (CT). Therefore, the silage quality of forage prepared from species‐rich mountain grasslands and the role CT may play in silage fermentation was studied. A set‐up of two long‐term mineral fertilization field experiments, located in the Jura mountains and the Alps in Switzerland were used to obtain forage with contrasting species and chemical composition. Collection was done during both the generative and vegetative growth stage from three differently fertilized swards: unfertilised (“0”), fertilized with phosphorus and potassium (“PK”) or fertilized with PK and nitrogen (“NPK”). The forage was wilted to approximately 37% dry matter (DM), chopped to 2 cm lengths and ensiled for at least 65 days as laboratory‐scale silages. The wilted forage was characterized by concentrations of crude protein between 117 and 130 g/kg DM and water‐soluble carbohydrates varying from 84 to 148 g/kg DM. Concentrations of CT ranged from 6 g to 14 g/kg DM and those of soluble CT from 1.8 to 7.6 g/kg DM. All silages contained butyric acid, irrespective of the type of fertilization or harvest stage (range: 1.5 g to 16 g/kg DM). Concentrations of acetic and lactic acid ranged from 2.1 g to 15.0 g/kg DM and from 21.0 to 44.0 g/kg DM, respectively. Concentrations of unfermented sugar remained high and pH levels were above those expected. Formation of non‐protein‐N (NPN) increased in the range of 130 to 264 g/kg N from wilted to ensiled forage. The negative correlations of CT or soluble CT contents with ammonia‐N or NPN in silage were found in both forage from the generative and vegetative harvests indicating a possible relationship with protein degradation during ensiling.

Short communication: Metabolization of benzoxazinoids during silage fermentation of maize and their effects on silage quality

The metabolization of phytochemicals like benzoxazinoids (BXs) during ensiling and storage are largely unknown. By comparing wild-type and BX-deficient maize lines, the present study investigated the turnover of BXs during silage formation and their effects on silage. The fermentation pattern of maize silage was primarily related to the chemical composition of chopped forage and the mode of preservation. The presence of BXs in the plants affected dry matter loss and fermentation products. Concentrations of benzoxazinone glucosides declined within the first 3 days of ensiling, whereas respective benzoxazinone aglycons accumulated until 4 weeks of ensiling. Under long-term anaerobic conditions, 2-hydroxy-7-methoxy-1,4-benzoxazin-3-one (HMBOA) and 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) represented the major fractions of BXs in maize silage, with 6-methoxy-1,3-benzoxazol-2-one (MBOA) and 1,3-benzoxazol-2-one (BOA) becoming the long-term end products of BX turnover in silage. Because benzoxazinoid derivatives are highly bioactive in other systems, they warrant more in-depth research for eventual effects on silage-feeding animals.

Cellulase–lactic acid bacteria synergy action regulates silage fermentation of woody plant

BackgroundFeed shortage is an important factor limiting livestock production in the world. To effectively utilize natural woody plant resources, we used wilting and microbial additives to prepare an anaerobic fermentation feed of mulberry, and used PacBio single-molecule real-time (SMRT) sequencing technology to analyse the “enzyme–bacteria synergy” and fermentation mechanism.ResultsThe fresh branches and leaves of mulberry have high levels of moisture and nutrients, and also contain a diverse range of epiphytic microorganisms. After ensiling, the microbial diversity decreased markedly, and the dominant bacteria rapidly shifted from Gram-negative Proteobacteria to Gram-positive Firmicutes. Lactic acid bacteria (LAB) emerged as the dominant microbial population, resulting in increased in the proportion of the carbohydrate metabolism and decreased in the proportion of the amino acid and “global and overview map” (GOM) metabolism categories. The combination of cellulase and LAB exhibited a synergistic effect, through which cellulases such as glycanase, pectinase, and carboxymethyl cellulase decomposed cellulose and hemicellulose into sugars. LAB converted these sugars into lactic acid through the glycolytic pathway, thereby improving the microbial community structure, metabolism and fermentation quality of mulberry silage. The GOM, carbohydrate metabolism, and amino acid metabolism were the main microbial metabolic categories during ensiling. The presence of LAB had an important effect on the microbial community and metabolic pathways during silage fermentation. A “co-occurrence microbial network” formed with LAB, effectively inhibiting the growth of harmful microorganisms, and dominating the anaerobic fermentation process.ConclusionsIn summary, PacBio SMRT was used to accurately analyse the microbial network information and regulatory mechanism of anaerobic fermentation, which provided a scientific basis for the study of woody silage fermentation theory. This study reveals for the first time the main principle of the enzyme–bacteria synergy in a woody silage fermentation system, which provides technical support for the development and utilization of woody feed resources, and achieves sustainable livestock production.

Effect of different conditions to forage before ensiling and use of a lactic acid bacteria-based additive on the fermentation and aerobic stability of maize silage

Effect of different conditions to forage before ensiling and use of a lactic acid bacteria-based additive on the fermentation and aerobic stability of maize silage

Efficacy of six lactic acid bacteria strains as silage inoculants in forages with different dry matter and water‐soluble carbohydrate content

AbstractThe dry matter (DM), water‐soluble carbohydrate (WSC) content, and epiphytic microbiota of forage during ensiling are critical for the production of high‐quality preserved forage. This study tested the efficacy of six additive treatments (106 CFU/g FM Lacticaseibacillus rhamnosus IMI 507023, Lactiplantibacillus plantarum [IMI 507026, IMI 507027, and IMI 507028] or Pediococcus pentosaceus [IMI 507024 and IMI 507025]) as ensiling agents for grass‐clover preservation. Treated and untreated forages were ensiled in 1.75 L glass jars and stored for 90 days at 20 ± 2°C. The effects of treatments on silage fermentation and aerobic stability were tested using grass‐clover forage at low and high levels of DM (24.0%–40.1%) and WSC (1.78%–5.27%). Data analysis using a mixed‐effects model and principal component analysis revealed improved silage fermentation in treated forages compared to that in the control. The fermentation‐related analytes in the treated silages (low pH, ethanol, acetic acid, and high lactic acid) represented a typical homofermentative metabolic pathway. The silage inoculants significantly lowered DM losses and ammonia‐N, % of total nitrogen content, ranging between 30.4%–52.5% and 30.5%–63.1% respectively, compared to the control. Additionally, forage type interacted with treatment, indicating that forage management is vital for ensiling and should be considered alongside inoculant use. The improvement in aerobic stability by lactic acid bacteria (LAB) was inconsistent. The principal component analysis of all analytes showed that aerobic stability was most closely correlated with acetic acid and butyric acid concentrations. In conclusion, all LAB strains successfully improved the preservation of forage materials.