Silage Fermentation Research Articles

The effect of including agro-industrial by-products on the fermentation pattern of grass silage and the performance of sheep: a meta-analysis

ABSTRACT The objectives of this study were to evaluate the effects of adding agro-industrial by-products (BP) on the fermentation pattern of grass silage (GS; objective 1) and on the performance of sheep (objective 2). Silage quality (dataset composed of 37 studies with 179 treatment means) was evaluated using the weighted mean difference (WMD) between the control (GS) and treatment (GS with BP) groups. Sheep performance (dataset composed of 7 studies with 23 treatment means) was evaluated using the WMD between the control diet (DGS = diet + GS without BP) and treatment diet (DGS-BP = diet + GS with BP). Treatment means were weighted by the inverse of the variance. The type of BP and harvest period of GS were the main covariates that influenced the effect of BP inclusion on the silage fermentation characteristics. The inclusion of BP in GS reduced pH, N-NH3, acetate, and butyrate and increased lactic acid concentration and lactic acid bacterial count. The type of BP and storage time were the main covariates that influenced the performance of sheep to DGS-BP. The DGS-BP inclusion in diet increased crude protein and neutral detergent fibre intake, total digestible nutrient digestibility, and the carcass weight of sheep.

Effects of cutting schedule and inoculation on chemical composition, ensiling characteristics and digestive utilisation of alfalfa silages

ABSTRACT The objective of this study was to evaluate the effects of ensiling alfalfa cut in the morning or the afternoon with or without inoculant on chemical composition, ensiling characteristics, and digestive utilisation of alfalfa silages. Fresh forage was obtained from 3 plots of alfalfa, each one subdivided into 12 subplots. The experimental design was a 2 × 2 factorial (cut AM or PM and with or without inoculant), with three replications (alfalfa plots) and three subsamples (subplots). Forage from each subplot was employed to fill one experimental silo. Variables of chemical composition, fermentation characteristics, and in vitro digestive utilisation were determined. Data obtained were analysed by a mixed procedure and least square means were compared. Correlations between variables of chemical composition of original forage and composition and fermentation of silages, as well as between variables of chemical composition and digestive utilisation of silages were analysed. PM cutting led to silages with higher content of remaining soluble sugars (P = 0.01), lower pH (P < 0.01), lower NH3–N concentration (P = 0.02), and higher IVTDMD (P = 0.03) than silages made in the morning. Providing enough WSC through cutting forage in the afternoon led to improvements in conservation quality and in vitro digestive utilisation and was more effective than inoculating alfalfa.

Sustainable use of agricultural residues to improve corn silage quality: Co-ensiling with oregano oil residues

The study aimed to evaluate the effect of oregano essential oil extraction residues (ORES) on the fermentation quality of corn silage. Non-fungal infected (NFI) and fungal infected (FI) corn were ensiled with 20% (wet weight) of ORES for 180 d. The inclusion of ORES delayed pH decline regardless of fungal infection. The inclusion of ORES did not adversely affect lactic acid (LA) production in NFI silages but retarded the initial LA fermentation of FI silages. Co-ensiling corn with ORES significantly decreased ethanol content. Co-ensiling FI corn with ORES significantly increased the fungal Chao1 and Shannon indices compared to FI-CON silages but did not affect the bacterial Chao1 and Shannon indices. The fungal infection aggravated the risk of Paenibacillus and Clostridium contamination, which was mitigated by co-ensiling with ORES. In conclusion, fungal infection suppressed ensiling fermentation, and heightened the risk of proliferation of undesirable bacteria, while ORES relieved these risks. Ensiling ORES with corn as forages is a potential and promising strategy for the efficient reusing of agro-industrial waste.

Honeysuckle branches and lactobacillus enhance quality by changing the composition and diversity of microorganisms in alfalfa silage fermentation

The incorporation of honeysuckle as a silage additive in alfalfa production has yielded promising results; however, the underlying microbial mechanisms during fermentation remain poorly understood. This study leveraged high-throughput sequencing and nutrient profiling to elucidate microbial population dynamics over 45 days of anaerobic fermentation within a vacuum-assisted co-culture system comprising varying fresh weight ratios of honeysuckle branches, Lactobacillus, and alfalfa. The experimental design encompassed a Lactobacillus-supplemented treatment (M group) and an unsupplemented control (R group), each with five honeysuckle percentages (5%, 10%, 15%, 20%, 25%) and respective negative controls. Our findings reveal that the combined use of honeysuckle branches and Lactobacillus significantly impacts microbial community composition and diversity during alfalfa silage fermentation. The Mantel test underscores Lactobacillus's absence-dependent correlation of bacterial communities with pH and lactic acid, whereas its presence redirects these correlations towards total nitrogen, NH4+-N, neutral detergent fiber, and crude protein as key bacterial population drivers. Fungal populations exhibited analogous trends. Moreover, the combined additives reshaped microbial populations during anaerobic fermentation, altering interaction networks and intensifying microbial interplay. Notably, Lactobacillus introduction on a honeysuckle branch base diminished fungal core OTUs, thereby mitigating fungal contamination risks. This study also identified biomarkers unique to each treatment condition. Collectively, our research provides a molecular framework for employing honeysuckle branches and Lactobacillus as innovative silage additives in alfalfa production, fostering the development of eco-friendly and hygienic feed and farming industries.

Nitrogen fertilisation method affects wheat silage ammonia-N and crude protein content

ABSTRACT This study aimed to evaluate the nitrogen fertilisation supply method on wheat silage fermentation parameters and nutritional value. Eighteen experimental plots were used in a randomised block design to assess the following treatments: (1) control (CON): crop without nitrogen fertilisation; (2) surface (SUR): 100 kg/ha N during the crop, applied in surface; (3) furrows (FUR): 100 kg/ha N during the crop, applied in furrows during the seeding. Whole plants were manually harvested at 5 cm height 83 days after the sowing. One experimental silo (PVC tubes) was produced for each agronomical plot and stored for 69 days. In general, N fertilisation did not affect silage pH and ammonia-N (NH3-N) content, but silos FUR had less NH3-N than those with SUR. Fertilisation increased the CP and DM content and reduced starch in the silage. FUR increased DM and reduced CP compared to SUR. Furthermore, N fertilisation increased non-protein nitrogen and decreased in vitro degradation of DM and OM. Fertilisation methods did not affect N fractions in silage or in vitro degradation. Therefore, N fertilisation, especially FUR, reduces NH3-N and CP and increases DM content of silage, but decreases in vitro DM and OM degradation.

The influence of the homofermentative lactic acid bacteria and enzymes on the nutritional value, health safety, and aerobic deterioration of the different maize hybrid silages

The research aimed to determine the impact of identic inoculants of lactic acid bacteria (LAB) with enzymes (ENZ) on the silage quality of 5 different corn hybrids (Zea mays). Hybrids (Pioneer Hi-Bred DuPont) differed by FAO maturity group (from early H1, mid-early H2, medium H3, mid-late H4 to late H5). Inoculant LAB consisted of a mixture of homofermentative bacteria: Lactobacillus plantarum, Enterococcus faecium, Pediococcus acidilactici, Lactobacillus salivarius, and ENZ: cellulase, α- amylase, hemicellulase, xylanase. Ensiling was done at the laboratory conditions, where the green mass of corn hybrids has been inoculated with LAB and ENZ were added, before ensiling. The process of ensiling lasted 60 days. The addition of LAB inoculants with ENZ is frequently used to speed up the ensiling process, prevent the growth of harmful microorganisms, protect the aerobic stability of silage, and improve the silage quality of different crops. The phase of aerobic degradation of silage begins immediately after exposure to silage to air. This stage is inevitable during feeding with silage and takes place in all silages, regardless of quality. The same pattern of reaction on identic LAB and EFEs addition was not found in silages ensiled from different hybrids. Among the evaluated corn hybrids, the additive to H1 early maturity hybrid had significantly improved the silage quality, and prolonged the time of aerobic stability, mainly due to the significantly highest CP, lowest ADL, and highest LA content. The chemical composition, fermentation, and microbiology profiles of silage significantly influence CO2 production in a test of aerobic stability (AS), and this is a causal relationship of aerobic stability duration. The results of this trial showed that the lower butyric acid, total microorganisms number, count of yeasts and mold, pH, and higher LAB, lactic acid, and acetic acid levels (P&lt;0.05), are accompanied by the production of lower CO2 (P&lt;0.05). The current research and previous studies suggest that nutritional value, health safety, and aerobic deterioration of the different maize hybrid silages are under the influence of epiphytic microflora of ensiled plants, used LAB inoculum, and EFEs addition in the appropriate amount, and the type of hybrid ensiled as well.

Multi-omics analysis reveals the core microbiome and biomarker for nutrition degradation in alfalfa silage fermentation.

Silage fermentation is a microbial-driven anaerobic process that efficiently converts various substrates into nutrients readily absorbable and metabolizable by ruminant animals. This study, integrating culturomics and metagenomics, has successfully identified core microorganisms involved in silage fermentation, including those at low abundance. This discovery is crucial for the targeted cultivation of specific microorganisms to optimize fermentation processes. Furthermore, our research has uncovered signature microorganisms that play pivotal roles in nutrient metabolism, significantly advancing our understanding of the intricate relationships between microbial communities and nutrient degradation during silage fermentation.

Dynamics of fermentation quality, bacterial communities, and fermentation weight loss during fermentation of sweet sorghum silage

BackgroundSweet sorghum is used mainly as an energy crop and feed crop in arid and semiarid regions, and ensiling is a satisfactory method for preserving high-quality sweet sorghum. The aim of this study was to reveal the dynamics of the fermentation quality, bacterial communities, and fermentation weight loss (FWL) of sweet sorghum silage during fermentation.MethodsSweet sorghum was harvested at the first inflorescence spikelet stage and ensiled without (CK) or with lactic acid bacterial (LAB) additives (L). After ensiling, samples were collected on days 0, 1, 3, 5, 15, 40, and 100 to assess the fermentation quality, bacterial communities, and FWL.ResultsFor CK and L, on day 1, the pH was 5.77 and 5.57, respectively, and the lactic acid (LA) was 1.30 and 2.81 g/kg dry matter (DM), respectively. Compared with CK, L had a lower pH and higher LA from days 1 to 5 (P < 0.05), a lower FWL from days 5 to 100 (P < 0.05), and a greater abundance of Lactiplantibacillus from days 1 to 15 (P < 0.05). The main bacterial genera were Leuconostoc and Weissella in CK and Lactiplantibacillus, Leuconostoc, and Weissella in L on day 1; Lactiplantibacillus in all silages from days 3 to 40; and Lactiplantibacillus and Lentilactobacillus in all silages on day 100.ConclusionsSweet sorghum silage fermented relatively slowly during the first day. Moreover, inoculation with LAB accelerated fermentation and optimized bacterial communities during the initial fermentation phase. Inoculation with LAB also reduced the silage FWL, and the LAB succession relay occurred in the silage throughout the fermentation process.

Transfer of pesticides and metabolites in corn: Production, processing, and livestock dietary burden

Corn stover is widely used in livestock feed but has received limited attention regarding its potential risks. In this study, pesticide residues were monitored across 12 provinces in China, and terminal residues of four pesticides, chlorantraniliprole, thiamethoxam, epoxiconazole, and pyraclostrobin, were tested. In addition, the silage processing experiment was conducted. All processing factors (PF) were <1, indicating pesticide degradation. The physicochemical properties of pesticides, especially log P, were related to degradation efficiency. Pesticides with higher log P values showed higher PFs (0.43 to 0.85), indicating lower degradation efficiency. The dietary burden of livestock before and after silage processing was calculated using OECD livestock dietary burden calculator. Results showed that after silage fermentation, the dietary burden was reduced by 28.8 % to 79.2 %. Throughout the entire production and processing process, the fastest degradation of all pesticides in whole corn was primarily observed from the pesticide application time to the harvest time, with some pesticides also showing accelerated degradation during subsequent processing stages. Therefore, in actual production, especially for pesticides which are difficult to degrade, appropriate extension of the safety interval or selection of suitable processing methods can be taken to further reduce pesticide residues in agricultural products.

Innovative Lactic Acid Production Techniques Driving Advances in Silage Fermentation

Lactic acid (LA) plays a crucial role in the silage process, which occurs through LA fermentation. Consequently, there is a strong correlation between lactic acid production and the efficiency of the silage. However, traditional methods face challenges like long fermentation times, low acid production, and unstable quality, limiting agricultural preservation. This paper aims to explore innovations in lactic acid production technologies and show how these technologies have driven the development of silage fermentation for agricultural conservation. First, the important role of LA in agricultural preservation and the limitations of traditional silage techniques are presented. Next, advancements in LA production methods are thoroughly examined, covering the selection of microbial strains and the substitution of fermentation substrates. Following this, new technologies for silage fermentation are explored, drawing from innovations in LA production. These include the selection of LA strains, optimization of fermentation conditions, and improvements in fermentation techniques. These innovations have proven effective in increasing LA production, improving feed quality, extending shelf life, and providing new solutions to enhance agricultural production and sustainability.

Influence of Ensiling Timing and Inoculation on Whole Plant Maize Silage Fermentation and Aerobic Stability (Preliminary Research)

Despite efforts to prevent atypical ensiling conditions, such as delayed ensiling or sealing, these issues frequently occur in practice. This study aimed to investigate the effects of delayed ensiling (forage held for 24 h) and sealing, along with inoculation using a blend of Lentilactobacillus buchneri and Lactococcus lactis, on the characteristics of the resulting silages. Whole-plant maize (Zea mays L.) was treated with or without a commercial inoculant and ensiled (36% dry matter) for 60 days in 3.0 L glass containers. The forage was either ensiled immediately or subjected to a 24 h delay before ensiling. During the delay, the forage was either covered or left uncovered. Each treatment was replicated five times. All data were analyzed using the MIXED procedure of SAS statistical software (version 9.4; SAS Institute Inc., Cary, NC, USA). Delaying the ensiling process by 24 h worsens fermentation parameters, significantly increases dry matter (DM) losses (p &lt; 0.01), and significantly reduces aerobic stability and the hygienic quality of the silage (p &lt; 0.01), as evidenced by higher concentrations of undesirable fermentation products and elevated yeast and mold counts. The inoculation has a significant impact on both forage before ensiling and the characteristics of the resulting silage. Maize forage treated with inoculant showed a lower temperature increase by 8.2–8.1 °C (p &lt; 0.01) when delayed for 24 h before ensiling. In silages, it also resulted in a reduced pH (p &lt; 0.01); increased concentrations of lactic acid; acetic acid; and 1,2-propanediol (p &lt; 0.01); and decreased levels of negative fermentation indicators such as ammonia-N, alcohols, and butyric acid (p &lt; 0.01) During both the fermentation and aerobic exposure periods, inoculated silages exhibited up to 36% and 2.6 times lower (p &lt; 0.01) dry matter loss, while suppressing the growth of yeasts and molds by up to 2.6 and 3.1 times (p &lt; 0.01), respectively, compared to non-inoculated silages. The results of this study support the recommendation to minimize the duration of aerobic exposure of fresh forage during silo filling and to use LAB-based inoculants.

Effects of Different Additives and Ratios on Broom Sorghum Straw Silage Characteristics and Bacterial Communities

As a large agricultural country, China produces a large number of agricultural and sideline products while harvesting agricultural products every year. Crop straw is one of them. Broom sorghum is a traditional crop in China, which produces a large amount of straw resources every year. These straw resources are placed in the field and cannot be used efficiently. The purpose of this study was to solve the problem of straw utilization of Broom sorghum, one of the main food crops in arid and semi-arid areas of northern China. Broom sorghum is not only a nutritious food crop, its straw is also rich in crude fiber and mineral elements, which has high utilization value. However, due to the high content of lignocellulose in straw, the texture is hard, which limits its digestion and utilization efficiency as feed. In this study, the broom sorghum straw was used as the research object, and the straw raw materials were treated with Lactobacillus plantarum, cellulase and xylanase, respectively. After silage fermentation for 30 d and 60 d, the bags were opened to determine the nutritional quality, fermentation quality, microbial community structure and other indicators. The best fermentation time and additives for broom sorghum straw silage were comprehensively screened to improve the nutritional value of straw and animal production performance. The results showed that the nutritional quality of silage straw increased with the extension of fermentation time. Compared with silage straw after 30 days of fermentation, the nutritional quality and fermentation quality of straw were significantly improved after 60 days of fermentation. Lactobacillus plantarum, cellulase and xylanase could improve the silage performance of broom sorghum straw by improving the microbial community structure in straw, and the effect of cellulase was the best. When cellulase was used in straw at the standard of 20 U/g FM, the content of water-soluble carbohydrates could be significantly increased to 31.35 g/kg FM, and the concentration of lactic acid was also significantly increased to 23.79 g/kg FM. Therefore, in actual production, it is recommended to use cellulase at a dose of 20 U/g FM in broom sorghum silage and open the bag after 60 days of silage fermentation. The results of this study provided a scientific basis for the efficient utilization of broom sorghum straw as feed.

Novel mechanistic understanding that Lactiplantibacillus plantarum is more capable of improving the ensiling performance of wheat straw silage than xylanase by driving certain key metabolites

Microbial and enzyme additives can improve silage performance, but there is limited comparative research on the effects of microbial and enzyme additives on improving silage fermentation quality, and the underlying microbial and metabolic pathways remain unclear. This study investigated the effects without inoculants (CK treatment) or with Lactiplantibacillus plantarum (LP treatment), xylanase (XY treatment) and their combination (LPXY treatment) on the fermentation quality, as well as on the microbial communities and metabolite profiles of the wheat straw silage. The results demonstrated that the LP treatment has a better effect on improving the fermentation quality of wheat straw silage compared to other treatments, as evidenced by markedly (p < 0.05) decreased the pH (4.06), acid and neutral fiber (ANF, NDF, 23.43 and 31.69%DM), and increased the lactic acid (LA, 965.89 mg/L) and acetic acid (AA, 656.10 mg/L) concentrations. After the fermentation process, the LP treatment significantly (p < 0.05) enhanced the abundance of Lactobacillus, reduced bacterial Shannon (p < 0.05) and increased some key metabolites content. The structural equation models (SEMs) and Pearson’s correlation results proved that the LP treatment improved the wheat straw silage fermentation quality via increasing the abundance of Lactobacillus, decreasing the diversity of bacterial community and enriching the content of certain key metabolites. The present study provides mechanistic evidence that Lactiplantibacillus plantarum additive is superior to xylanase additive and their combination on improving fermentation quality of wheat straw silage, that is, by enriching certain key metabolites to increase AA and LA concentrations, providing a reference for the cross study of silage feed fermentation microbiome and metabolome.Graphical

Translating 2D-Chromatographic Fingerprinting to Quantitative Volatilomics: Unrevealing Compositional Changes in Maize Silage Volatilome for Robust Marker Discovery.

This study examines the complex volatilome of maize silage, both with and without commercial heterolactic strain inoculation, conserved for 100 days, using quantitative volatilomics. Chemical classes linked to microbial metabolism were analyzed across a concentration range from 10 μg g-1 to 1 ng g-1. A reference method using comprehensive two-dimensional gas chromatography (GC × GC) and time-of-flight mass spectrometry (TOF MS) with loop-type thermal modulation (TM) was translated to a differential-flow modulation (FM) platform with parallel MS and flame ionization detector (FID) detection. With translation, the original method's analyte elution order and resolution are preserved. The new method allowed for accurate quantification using multiple headspace solid-phase microextraction (MHS-SPME) and FID-predicted relative response factors (RRFs). Both methods showed comparable discriminatory power with FM GC × GC-MS/FID achieving satisfactory quantification accuracy without external calibration. Analysis of 98 volatiles provided insights into silage fermentation, supporting marker discovery and correlations with silage quality and stability.

Effect of acid and fermented silage hydrolysis time on protein fractionation and digestibility for Nile Tilapia

World aquaculture production currently demands sustainable protein ingredients that can compete with fishmeal regarding nutritional quality and economic feasibility. In this study, the protein fractionation of silages prepared with Nile tilapia processing waste (heads, spine, fins, and viscera) by two processes and three hydrolysis times was evaluated, considering the digestibility coefficients of its crude protein, amino acids, and gross energy of Nile tilapia juveniles. The apparent digestibility coefficients (ADCs) were determined using 360 Nile tilapia juveniles (9.36 ± 0.74 g) distributed in 18 tanks (150 L), following a completely randomized design with six treatments, in a factorial scheme of 2×3, with three replicates. The six test diets were composed of 69.5 % of the reference diet, 0.5 % chromium (III) oxide, and 30 % of either acid or fermented silages produced with three hydrolysis times (24, 96, and 192 hours). The results demonstrated that both the processing type and hydrolysis time influenced the profile and peptide fractions of the silages. The acid silage was faster in relation to the release of free α-amino groups and the degree of hydrolysis (DH), up to 192 hours of hydrolysis. After this period, the fermented silage showed a higher degree and speed of hydrolysis. SDS-PAGE demonstrated that a longer hydrolysis time increased the concentration of the protein band between 150 and 100 kDa, indicating a proliferation of microorganisms using the free amino acids produced during fermentation. Regarding the distribution of peptides, acid silage presented higher values for the concentration of polypeptides, slow degradation and proportion among fractions, with the appearance of di- and tripeptides, as well as free amino acids. For the fermented silage, a higher degradation of polypeptides into oligopeptides was verified, representing the highest fraction, with a small proportion of di- and tripeptides and free amino acids. ADC values were high for all amino acids and proteins, which was not observed for the mean values of energy ADC. The production of silages with 192 hours of hydrolysis proved to be viable, and the fermented processing revealed the highest ADC values in relation to most of the amino acids, thus being the most indicated to be incorporated in fish diets, favoring its utilization by small farmers and reducing the inadequate disposal of biodegradable waste, thereby avoiding environmental pollution.

Isolation and screening of high biofilm producing lactic acid bacteria, and exploration of its effects on the microbial hazard in corn straw silage

Silage is a well-established method for preserving feed. However, the preparation process still poses several potential microbial hazards. Lactic acid bacteria exhibiting a biofilm phenotype are considered the most advanced 'fourth-generation probiotics' due to their significant potential in enhancing fermentation quality. In this study, a strain of high-biofilm-producing lactic acid bacteria (HBP-LAB) was successfully isolated from silage samples using the crystal violet method and designated as Lactiplantibacillus plantarum S23Y. This strain was subsequently used as an inoculant in corn straw for experimental purposes. The results indicated that it effectively reduced dry matter loss caused by microorganisms, thereby enhancing the retention of dry matter in silage. Following aerobic exposure, this strain was able to maintain the population of Lactobacillus and the concentration of lactic acid, which significantly decreased the likelihood of yeast-induced aerobic spoilage and improved the aerobic stability of the silage. However, it is important to note that this HBP-LAB did not have a significant impact on antibiotic resistance genes (ARGs) or mobile genetic elements (MGEs) in the silage. In conclusion, using S23Y as a representative strain, we have demonstrated that HBP-LAB can enhance the fermentation quality of silage to a certain extent and mitigate the detrimental effects of microorganisms. The findings of this study provide valuable insights for the application of lactic acid bacteria with a biofilm phenotype in silage fermentation.

Rapid Lactic Acid Content Detection in Secondary Fermentation of Maize Silage Using Colorimetric Sensor Array Combined with Hyperspectral Imaging

Lactic acid content is a crucial indicator for evaluating maize silage quality, and its accurate detection is essential for ensuring product quality. In this study, a quantitative prediction model for the change of lactic acid content during the secondary fermentation of maize silage was constructed based on a colorimetric sensor array (CSA) combined with hyperspectral imaging. Volatile odor information from maize silage samples with different days of aerobic exposure was obtained using CSA and recorded by a hyperspectral imaging (HSI) system. Subsequently, the acquired spectral data were subjected to preprocessing through five distinct methods before being modeled using partial least squares regression (PLSR). The coronavirus herd immunity optimizer (CHIO) algorithm was introduced to screen three color-sensitive dyes that are more sensitive to changes in lactic acid content of maize silage. To minimize model redundancy, three algorithms, such as competitive adaptive reweighted sampling (CARS), were used to extract the characteristic wavelengths of the three dyes, and the combination of the characteristic wavelengths obtained by each algorithm was used as an input variable to build an analytical model for quantitative prediction of the lactic acid content by support vector regression (SVR). Moreover, two optimization algorithms, namely grid search (GS) and crested porcupine optimizer (CPO), were compared to determine their effectiveness in optimizing the parameters of the SVR model. The results showed that the prediction accuracy of the model can be significantly improved by choosing appropriate pretreatment methods for different color-sensitive dyes. The CARS-CPO-SVR model had better prediction, with a prediction set determination coefficient (RP2), root mean square error of prediction (RMSEP), and a ratio of performance to deviation (RPD) of 0.9617, 2.0057, and 5.1997, respectively. These comprehensive findings confirm the viability of integrating CSA with hyperspectral imaging to accurately quantify the lactic acid content in silage, providing a scientific and novel method for maize silage quality testing.

Co-expression of endoglucanase and cellobiohydrolase from yak rumen in lactic acid bacteria and its preliminary application in whole-plant corn silage fermentation.

Endoglucanase (EG) and cellobiohydrolase (CBH) which produced by microorganisms, have been widely used in industrial applications. In order to construct recombinant bacteria that produce high activity EG and CBH, in this study, eg (endoglucanase) and cbh (cellobiohydrolase) were cloned from the rumen microbial genome of yak and subsequently expressed independently and co-expressed within Lactococcus lactis NZ9000 (L. lactis NZ9000). The recombinant strains L. lactis NZ9000/pMG36e-usp45-cbh (L. lactis-cbh), L. lactis NZ9000/pMG36e-usp45-eg (L. lactis-eg), and L. lactis NZ9000/pMG36e-usp45-eg-usp45-cbh (L. lactis-eg-cbh) were successfully constructed and demonstrated the ability to secrete EG, CBH, and EG-CBH. The sodium carboxymethyl cellulose activity of the recombinant enzyme EG was the highest, and the regenerated amorphous cellulose (RAC) was the specific substrate of the recombinant enzyme CBH, and EG-CBH. The optimum reaction temperature of the recombinant enzyme CBH was 60°C, while the recombinant enzymes EG and EG-CBH were tolerant to higher temperatures (80°C). The optimum reaction pH of EG, CBH, and EG-CBH was 6.0. Mn2+, Fe2+, Cu2+, and Co2+ could promote the activity of CBH. Similarly, Fe2+, Ba2+, and higher concentrations of Ca2+, Cu2+, and Co2+ could promote the activity of EG-CBH. The addition of engineered strains to whole-plant corn silage improved the nutritional quality of the feed, with the lowest pH, acid detergent fiber (ADF), and neutral detergent fiber (NDF) contents observed in silage from the L. lactis-eg group (p < 0.05), and the lowest ammonia nitrogen (NH3-N), and highest lactic acid (LA) and crude protein (CP) contents in silage from the L. lactis-eg + L. lactis-cbh group (p < 0.05), while the silage quality in the L. lactis-cbh group was not satisfactory. Consequently, the recombinant strains L. lactis-cbh, L. lactis-eg, and L. lactis-eg-cbh were successfully constructed, which could successfully expressed EG, CBH, and EG-CBH. L. lactis-eg promoted silage fermentation by degrading cellulose to produce sugar, enabling the secretory expression of EG, CBH, and EG-CBH for potential industrial applications in cellulose degradation.

PSVIII-8 The impact of foliar fungicide application on barley silage fermentation characteristics and performance of lactating dairy cows

Abstract Forages are an important component in dairy cow diets and barley silage is the primary forage source in western Canada and parts of the USA. Foliar fungal diseases can infect barley, thereby causing leaf damage and a loss of yield and quality. The objectives were to determine the effects of foliar fungicide application on two barley forage varieties, one resistant (CDC Fraser) and the other susceptible (Claymore) to foliar fungal disease, on silage ensiling characteristics and feed intake, milk production and composition, ruminal pH, and nitrogen (N) balance in dairy cows. Multiparous Holstein cows [n = 12; mean (ays in milk (DIM) = 40 ± 17; mean body weight (BW) = 720 ± 26 kg] at the start of the experiment) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of dietary treatments. Experimental periods were 25 d, with 18 d of dietary adaptation and 7 d of sample and data collection. Test diets were: 1) fungicide-treated Claymore silage (CF); 2) untreated Claymore silage (CNF); 3) fungicide-treated CDC Fraser silage (FF); and 4) untreated CDC Fraser silage (FNF) as the major source of forage. Forage yields were 1.86 (FNF), 1.46 (CNF), 1.17 (FF), and 1.35 (CF) t dry matter (DM)/ha, likely reflective of the low rainfall during the growing season. Experimental silages were similar in crude protein (mean = 14.0%; DM basis), ammonia (mean = 1.95%), and total volatile fatty acid (mean = 9.25%) concentrations. CDC Fraser silage had greater lactic acid concentration (P &amp;lt; 0.001) but decreased pH (P = 0.01) and acetic acid concentration (P &amp;lt; 0.01) than Claymore silage. Silage aNDF contents (DM %) were similar in FF and FNF, but greater in CNF than CF (interaction; P &amp;lt; 0.05). Without fungicide application, barley variety had no effect on silage starch content (DM %), whereas with fungicide application, Claymore had a greater silage starch content than CDC Fraser (interaction; P &amp;lt; 0.05). Dry matter intake, milk yield, and milk composition were unaffected by diet (P &amp;gt; 0.05). Total tract nutrient digestibility was unaffected by diet (P &amp;gt; 0.05). Intake of N, and urinary and fecal N excretion, total N excretion, milk N, and apparent N balance (expressed as g/d or % of N intake) were unaffected by diet (P &amp;gt; 0.05). Ruminal short-chain fatty acid (SCFA) concentrations and pH were unaffected by diet (P &amp;gt; 0.05); however, total SCFA concentration was similar in CF and CNF but was greater in FNF than FF (interaction; P &amp;lt; 0.05). Valerate concentration was similar in FF and FNF but greater in CF than CNF (interaction; P &amp;lt; 0.05). Foliar fungicide application on barley, regardless of variety susceptibility to fungal diseases, did not negatively affect silage quality or dairy cow performance.

Effects of Maize–Lablab Intercropping and Lactic Acid Bacteria Additives on Forage Yield, Fermentation Quality and Profitability

Intercropping systems and exogenous microorganism additives are recognized for their potential to influence silage fermentation and quality. This study aims to evaluate the impacts of maize–lablab bean intercropping and lactic acid bacteria (LAB) additives on silage yield, nutritional quality, and economic profitability. A randomized block design was employed with two cropping patterns—maize monocrop (M) and maize–lablab intercrop (ML)—and five additive treatments: No additives (CK), and varying ratios of Lactobacillus Plantarum (LP) and Lactobacillus Buchneri (LB), T1 (100% LP), T2 (9LP:LB), T3 (8LP:2LB), and T4 (100% LB). The silage was analyzed and evaluated for its nutritional quality, fermentation quality, and fermentation effect after 90 days of fermentation. ML intercropping significantly enhanced the fresh matter yields by 8.59% and crude protein content by 8.73% compared to M. From the point of view of inoculation with different lactobacilli, the pH, AA, and NH3-N/TN were lower in the T2 and T3 treatments than in the other treatments, while LA was significantly higher. The V-score, which reflects the overall fermentation quality, was excellent across all treatments, with scores exceeding 80 points; the T2 treatment in ML silage achieved the highest score of 99.58. In addition, intercropping can increase the net income of farmers by 21.67%. In conclusion, maize–lablab intercropping combined with LAB inoculation, particularly with the T2 and T3 treatments, significantly enhances the silage quality and economic returns by reducing pH, increasing the LA content, and improving the CP levels. This study is the first to comprehensively analyze the synergistic effects of altering cropping systems and adding functional microorganisms on forage yield and fermentation quality, offering strategic insights for farms, especially mixed farms, to produce high-quality feed. We recommend adopting these methods to improve feed quality and maximize the profitability of silage production systems.