Search Results (182)

Conifer-derived essential oils have gained attention as versatile natural additives with potential applications in animal production, including influencing microbial processes and supporting environmental sustainability. This study aimed to characterize the chemical composition of selected conifer essential oils (EOs), evaluate their antimicrobial activity against rumen microorganisms in vitro, and assess the effects of Pinus sylvestris essential oil on rumen fermentation and methane production under in vitro and in vivo conditions. EOs from Thuja occidentalis, Cupressus sempervirens, Juniperus communis, Picea mariana, Pinus sylvestris, and Pinus pinaster were analyzed by GC–MS, and their inhibitory activity against selected rumen bacteria was determined by MIC and IC₅₀ assays. Based on these results, P. sylvestris oil was selected for fermentation experiments. Ninety-two volatile compounds were identified, with monoterpenes as the dominant constituents and α-pinene as the major compound in P. sylvestris oil. In vitro, P. sylvestris oil influenced fermentation in a dose-dependent manner without affecting ruminal pH. In vivo, ruminal pH, ammonia-related parameters, and total VFA concentration were not significantly affected by treatment, whereas several variables showed a significant effect of time. Temporal changes in VFA profiles suggested a transient adaptation of ruminal fermentation. Methane concentration was significantly (p < 0.01) reduced by Pinus sylvestris essential oil supplementation, with a decrease of approximately 28.7% after 14 days. These findings indicate that P. sylvestris EOs may serve as a promising natural modulator of rumen fermentation, although further studies are needed to optimize dosage and confirm long-term effects. Full article

Lignocellulose is degraded in the rumen by diverse microorganisms. This study aimed to select the top ruminal microbes associated with an anaerobic fungus (AF) capable of forming consortia that facilitate biogas production from wheat straw. The workflow included the following steps: (1) batch reactors, divided into three compartments with porous membrane bags containing wheat straw, were assembled. The outermost compartment was inoculated with freshly collected rumen content. The first microbes colonizing the wheat straw in the innermost compartment within 72 h were identified. (2) Synthetic consortia were assembled comprising the following identified microbes: an anaerobic fungus (AF) (Neocallimastix lanati); methanogenic archaea (M) (Methanobrevibacter ruminantium or Methanobrevibacter gottschalkii); bacteria (B) (Butyrivibrio hungatei or Succinoclasticum ruminis). (3) Wheat straw was subjected to 7-day pretreatments with these synthetic consortia. (4) The pretreated straw served as substrate in biochemical methane potential (BMP) tests that used a biogas reactor digestate as the inoculum. The pretreated straw produced elevated biomethane yields; nonetheless, this process needs further optimization. The cross-kingdom AF + M + B consortia increased methane production by 35–70%, and superior volatile fatty acid production was confirmed via HPLC. The results suggest novel strategies for advanced practical biogas/biomethane technologies. Full article

This study aimed to investigate the effects of feeding high-moisture corn (HMC) on weight performance, serum immune and antioxidant indices, rumen fermentation, microbial community, and metabolomics in Kazakh rams. A total of 32 healthy Kazakh rams were randomly divided into a control group (CT, diet with only ordinary crushed corn) and an experimental group (GS, diet with 50% ordinary crushed corn + 50% HMC), following a 7-day adaptation period and a 120-day trial period. Results showed that the F/G was significantly lower in the GS group than in the CT group (p < 0.05). FBW, net weight gain and ADG increased by 4.58%, 8.69%, and 8.70%, respectively, while ADFI decreased by 7.04% (p > 0.05). Regarding serum immune indices, IgA in the GS group was significantly higher at 40 d (p < 0.01), and IgM was significantly higher at 40, 80, and 120 d (p < 0.05). For antioxidant indices, the SOD activity in the GS group was significantly higher than that in the CT group at 120 d (p < 0.01). The CAT activity in the GS group was significantly higher at 40, 80, and 120 d (p < 0.01). Among rumen fermentation parameters, the concentration of butyric acid in the GS group was significantly lower than in the CT group (p < 0.01). Microbial diversity analysis indicated no significant differences in Alpha- and Beta-diversity of rumen microorganisms between the two groups. However, the relative abundance of Firmicutes_A at the phylum level was significantly higher in the GS group (p < 0.05), and the abundance of Cryptobacteroides was significantly higher than in the CT group (p < 0.01). Rumen metabolomic analysis identified a total of 1357 differential metabolites, among which 1130 showed significant differences, with 459 upregulated and 671 downregulated. These were mainly enriched in pathways such as Glutathione metabolism, Beta-alanine metabolism, Sphingolipid metabolism, and lysine degradation. In conclusion, feeding HMC can improve feed conversion efficiency and weight performance in Kazakh rams, regulate the structure of dominant rumen microorganisms, and enhance immune and antioxidant capacities. Full article

The sensory quality and flavor of lamb meat, critical to market competitiveness, are influenced by rumen microbial fermentation and dietary management strategies. Coated betaine (CBet), a rumen-protected methyl donor, exerts systemic nutritional regulation in ruminants. This study explored the effects of CBet supplementation on lamb meat quality using 18 Dorset ♂ × Hu sheep ♀ F1 crossbred lambs, randomly assigned to either a control group (basal diet) or a 0.20% CBet-supplemented diet for 60 days (n = 9 per group). The results demonstrated that CBet significantly increased ruminal concentrations of total volatile fatty acids (TVFAs), acetic acid, propionic acid, and butyric acid (p < 0.05). Additionally, CBet supplementation enhanced muscle redness (a*), crude fat, crude ash, heptadecanoic acid (C17:0), and tricosanoic acid (C23:0) (p < 0.05) while decreasing shear force and the concentration of cis-13,16-docosadienoic acid (C22:2) (p < 0.05). Furthermore, CBet elevated characteristic flavor compounds (e.g., nonanal) and their relative odor activity values (ROAVs), and decreased undesirable odors (e.g., dodecanal) (p < 0.05). As illustrated in the graphical abstract, these improvements were mediated through regulatory effects of CBet on rumen microbiota composition, muscle fatty acids, amino acids, and volatile flavor compounds. Specifically, CBet significantly increased the relative abundances of Firmicutes, Proteobacteria, Prevotella, and Bifidobacterium in the rumen (p < 0.05) and altered the Firmicutes/Bacteroidota ratio. In conclusion, dietary supplementation with 0.20% CBet effectively enhances lamb meat quality and flavor, effects closely associated with changes in the abundance of key ruminal microbial taxa. Full article

Intramuscular fat (IMF) significantly influences meat quality, particularly flavor. The gastrointestinal microbiota can regulate lipid metabolism. The relationship between intramuscular fat metabolism, rumen microbiota, and beef quality remains unclear. This study enrolled 22 30-month-old Xinjiang Brown Beef cattle, which were randomly allocated to two groups: an intact bull group (n = 15) and a castrated bull group (n = 7). All experimental animals were housed and maintained under consistent feeding and management conditions throughout the entire experimental period. By combining in vivo ultrasonography, slaughter trials, rumen microbiome diversity analysis, and metabolomics techniques, and after adjusting for covariates including intramuscular fat (IMF) content, body weight, and backfat thickness, the present study demonstrated that castration regulates muscle lipid metabolism by reshaping the composition of the rumen microbial community, thereby exerting a cascading effect on key beef quality traits. (1) Production and meat quality: Live weight, carcass weight, eye muscle area, backfat thickness, and intramuscular fat (IMF) content were significantly higher in the YN group than in the GN group (p < 0.01). Conversely, dressing percentage, shear force value, and muscle protein content were significantly lower in the YN group than in the GN group (p < 0.01 or p < 0.05). (2) Rumen microbiota–metabolite correlation: Significant differences existed in microbial composition and community structure between groups (with significant differences in both α and β diversity). Core microbes regulated by castration exhibited distinct co-variation patterns with metabolites: genera such as Anaeroplasma showed significant positive correlations with hydroxy fatty acids, while Sharpea and others showed significant negative correlations with saturated fatty acids. (3) Microbial–metabolite axis and host phenotype correlation: Axes composed of Eubacterium uniforme and others showed significant positive correlations with IMF, while Docosapentaenoic acid (22n-3) exhibited significant negative correlations with IMF. Anaeroplasma and others showed significant positive correlations with oleic acid and others, as well as BFT, while saturated fatty acids showed significant negative correlations with BFT. (4) Covariate validation: After adjusting for covariates including body weight, backfat thickness, and IMF, castration was confirmed to significantly regulate the abundance/content of core genera such as Anaeroplasma, Eubacterium uniforme, as well as key metabolites such as hydroxy fatty acids and docosapentaenoic acid (22n-3) (p < 0.05 after adjustment), making it a core driver regulating rumen microbial composition and muscle lipid metabolism. After adjustment, the regulatory effects of IMF, body weight, and backfat thickness on the aforementioned microorganisms and metabolites were no longer significant (adjusted p > 0.05). Intramuscular fat (IMF), body weight, and backfat thickness are not independent drivers but rather indirect effects resulting from castration-induced physiological state remodeling. This study did not include feeding rate measurements, which represents a limitation. Future research should incorporate this data to further validate the conclusions. This study elucidates the interactive mechanisms between rumen microbiota and their metabolites, identifies the key pathways governing intramuscular fat (IMF) deposition, pinpoints potential regulatory targets for beef quality optimization, and clarifies the intermediate regulatory mechanisms underlying the modulation of meat quality traits by castration. Full article

Microplastic pollution is increasingly serious worldwide, threatening human and animal health. The cow rumen is a key organ for nutrient digestion and absorption, and its fermentation is closely related to rumen microorganisms. Here, we investigated how polystyrene microplastics (PS-MPs) with varying particle sizes and concentrations affect rumen fermentation and the biodegradability of PS-MPs by rumen fermentation. The results reveal that exposure to PS-MPs lowered gas production and gas concentrations, as well as volatile fatty acid content, and these decreases were positively correlated with PS-MP concentration. However, higher PS-MP concentration and larger particle size increased the activity of carboxymethyl cellulose, β-glucosidase, and xylanase. Furthermore, PS-MP exposure reduced the abundance of certain rumen microorganisms and altered metabolic pathways and metabolites linked to PS-MP biodegradation. It was also found that PS-MP content decreased significantly after 24 h fermentation. Therefore, PS-MPs can inhibit rumen fermentation by affecting the rumen microbiome, and rumen microorganisms and their secreted enzymes can biodegrade PS-MPs to produce styrene and derivatives; such small molecules may further disrupt rumen homeostasis, thereby affecting lactation performance. In addition, rumen microbial degradation of PS-MPs provides a new idea to resolve future microplastic contamination challenges. Full article

The combination of additives in ruminant diets is a growing strategy focused on cow health and productivity; therefore, the additives need to have synergistic effects when combined. Because of this, the objective of this study was to evaluate the effects of combining functional additives (biocholine, live yeasts, Yucca schidigera extract, and exogenous enzymes) on the productive performance, milk quality, rumen environment, oxidative status, and metabolic parameters of lactating Jersey cows maintained in an intensive system as well as verifying whether the effects on metabolism and the rumen environment (volatile fatty acids and microbiota) directly or indirectly influence productive efficiency. Eighteen Jersey cows in their second lactation were used, distributed in a completely randomized design into two groups: control, receiving a basal diet, and treatment, receiving the same diet plus the additive mixture. The experiment lasted 56 days. Dry matter intake, milk production and composition, feed efficiency, apparent digestibility, volatile fatty acid profile, rumen microbiota, hematological and biochemical parameters, and oxidative stress markers were evaluated. The combination of additives was able to increase milk production and production corrected for fat, protein, and energy, without altering dry matter intake, resulting in greater feed efficiency. There was an increase in milk protein content from day 28 onwards. In the rumen, a reduction in the protozoan population and an increase in the proportion of propionic acid were observed, without altering the ruminal pH or the total production of volatile fatty acids. The apparent digestibility of crude protein was higher in the treated group. The consumption of additives also promoted specific changes in the ruminal microbiota, with a greater abundance of microorganisms associated with carbohydrate degradation and less activity of pathways related to denitrification. From a systemic point of view, the treatment reduced markers of oxidative stress (reactive oxygen species—ROS and thiobarbituric acid reactive substances—TBARS), decreased creatine kinase and cholinesterase activity, and increased serum fructosamine concentration, indicating antioxidant, anti-inflammatory effects and improved energy status, respectively. It is concluded that the combination of plant biocholine, yeasts, Yucca schidigera extract, and exogenous enzymes improves productive efficiency, promotes ruminal fermentation, and contributes to greater metabolic and oxidative stability in lactating Jersey cows. Full article

This study aimed to quantitatively determine the composition of 25 essential oils (EOs) using gas chromatography–mass spectrometry (GC-MS) to assess their minimum inhibitory concentrations (MICs) against selected rumen microorganisms and to confirm their effects in in vitro tests on volatile fatty acid (VFA) formation. GC-MS analysis identified over 80 compounds across the tested oils. The MICs were determined for Butyrivibrio fibrisolvens, Prevotella albensis, Lactobacillus delbrueckii ssp. lactis, and Streptococcus bovis, revealing diverse sensitivities. The rumen bacteria’s sensitivity to essential oils varied by strain, with some microorganisms inhibited at low concentrations while others required higher doses, highlighting the potential for targeted modulation of the rumen microbiota. Amyris balsamifera and Zingiber officinale demonstrated strong inhibitory effects at low concentrations and simultaneously enhanced VFA production. In contrast, Lavandula officinalis showed inhibitory effects on VFAs. Amyris balsamifera and L. officinalis also exhibited methane reduction. These findings demonstrate that selected essential oils can modulate rumen microbiota and fermentation by either inhibiting or stimulating specific bacterial groups, highlighting their potential as natural modulators to improve rumen function and animal health. Full article

Acidogenic fermentation is a promising biotechnology for converting organic wastes into carboxylic acid (CA), which has significant commercial value and diverse applications in the food, chemical, pharmaceutical, and cosmetic industries. However, major challenges such as limited substrate hydrolysis and lower CA production hinder further development of this biotechnology towards full-scale implementation. This review provides a comprehensive overview of the current status of acidogenic fermentation, focusing on substrate composition, inoculum, and reactor design, along with potential strategies to overcome reactor-specific limitations and enhance CA production. It was found that the substrate composition, particularly its carbohydrate, protein, and lipid contents, strongly influences both CA production and yield. Specifically, carbohydrate-rich substrates yield higher CA production compared to protein- and lipid-rich substrates. These substrates have been investigated in different reactor configurations for CA production. Among them, the leachate bed reactor and anaerobic membrane bioreactor have demonstrated superior performance, achieving higher CA production with acetic and butyric acids as the dominant CA composition. These reactors are generally operated using three types of inocula: aerobic and anaerobic inoculum, enriched inoculum, and rumen microorganisms. Interestingly, rumen microorganisms are effective in degrading complex substrates, whereas enriched inoculum accelerates hydrolysis and acidogenesis processes within a shorter fermentation time. The findings presented herein will provide valuable information for addressing the challenges associated with acidogenic fermentation and lay the foundation for future research aimed at upscaling this biotechnology to a commercial scale. Full article

Few studies have examined the effects of puerarin (PE) on ruminant parameters and methane production. Therefore, we determined the degradation of PE in the rumen and evaluated the effect of PE on in vitro fermentation, methanogenesis, and microbial community structure. A completely randomized design was used for the in vitro fermentation, and 4 gradient dosages of PE (0 mg/kg, 50 mg/kg, 100 mg/kg, and 150 mg/kg of DM) were applied in this trial. The in vitro fermentation was carried out in three runs at 6 h and 48 h, with four replicates per treatment per time point. Each run included 40 samples: eight treatments × four replicates and eight blank samples. Based on the fermentation results, both the PE treatments and the control group (CON) at 48 h were chosen for further analysis to explore the effects of PE on the bacterial community structure. Meanwhile, we determined the degradation rate and degradation products of PE in vitro ruminal fluid using high-performance liquid chromatography (HPLC). In this trial, PE may be isomerized into daidzin by rumen microorganisms; the in vitro degradation results of PE indicated that 70% of PE was degraded within 6 h, with the degradation rate reaching nearly 85% by 12 h. The concentrations of NH₃-N and microbial crude protein (MCP) significantly increased linearly with the PE doses at 6 h (p = 0.01). The concentrations of MCP (p = 0.02) and propionate (p = 0.04) demonstrated a linear increase with increasing PE doses at 48 h. In contrast to microbial protein (MCP) and propionate, the acetate-to-propionate ratio decreased linearly with increasing PE doses at 48 h (p = 0.05). Additionally, the addition of PE linearly decreased methane production at 48 h (p = 0.01). Meanwhile, the relative abundances of g_UBA1217 (p = 0.03), g_UBA2810 (p = 0.04), and g_Succiniclasticum (p = 0.03) were significantly lower compared with the CON group. The results showed that PE can be degraded by rumen microflora. Furthermore, it can improve rumen fermentation parameters, increase the amount of protein synthesized by rumen microorganisms, and reduce methane production and the acetate-to-propionate ratio. PE could potentially be an effective strategy for methane mitigation; however, further research is needed to assess its in vivo effects in dairy cows over a longer period. Full article

Mycotoxins are toxic compounds produced by certain types of fungi that can contaminate animal feed. Cattle may be exposed to these toxins through contaminated feed sources such as cereal grains (e.g., corn, barley), silage, hay, and other roughages, where aflatoxins, fumonisins, T-2 toxins, zearalenone, deoxynivalenol, ochratoxins, and emerging mycotoxins are most commonly found. Cattle are generally less sensitive to mycotoxins, mainly due to detoxification processes occurring in the rumen. The rumen plays a key role in the degradation or transformation of mycotoxins through the activity of ruminal microorganisms and enzymes before these toxins are absorbed into the bloodstream. However, despite this natural defense, mycotoxins have been shown to impact ruminant health. This article aimed to analyze the literature on the negative effects of mycotoxin exposure on cattle health. In January 2025, a systematic search of various databases (PubMed, Google Scholar, EMBASE, and Web of Science) was conducted in Google Chrome to identify studies assessing the association between mycotoxin exposure and health complications in cattle. Symptoms of mycotoxin poisoning are nonspecific and include metabolic and hormonal imbalances, inflammatory conditions, weakened immune response, digestive disorders, reduced productivity, and reproductive issues. These toxins may also compromise the safety of the food chain, including the quality of milk and meat products. Due to the increasing risk of mycotoxin contamination in feed, a comprehensive approach to feed management is essential. This includes regular monitoring, proper storage of raw materials, and the use of plant protection products that minimize the risk of contamination. Full article

Extensive growth promoter use in livestock production has raised concerns about their role in selective pressure on resistant microorganisms, driving interest in natural alternatives such as essential oils (EOs). This study aimed to evaluate the effects of tea tree, holy wood, and citronella EOs on in vitro ruminal fermentation. The study follows a completely randomized design with the following five treatments: control, monensin (5 μM), tea tree EO (50 mg/L), holy wood EO (50 mg/L), and citronella EO (50 mg/L), each conducted in triplicate. Incubations were performed at 39 °C for 48 h in the rumen fluid collected from fistulated cattle fed a 20:80 forage-to-concentrate diet. Notably, EOs exhibited no significant effects on pH, microbial protein production, total volatile fatty acids, or in vitro dry matter digestibility (p > 0.05). Tea tree and holy wood EOs enhanced deamination activity, and all treatments increased ammonia concentration compared with that in the control. Monensin treatment increased acetate concentration and reduced in vitro neutral detergent fiber digestibility; holy wood EO exhibited a similar trend. Altogether, the findings of this study suggest that EOs can selectively modulate the ruminal microbiota, influencing nitrogen metabolism and fermentation patterns without impairing rumen stability. Full article

This study aims to investigate the effect of varying addition levels of corn steep liquor (CSL) on the fermentation quality, bacterial community, and ruminal degradation rate of corncob silage. The experiment included a control group (CON) and four treatment groups: L1 with 5% CSL (50 g·kg⁻¹ fresh matter), L2 with 10% CSL (100 g·kg⁻¹ fresh matter), L3 with 15% CSL (150 g·kg⁻¹ fresh matter), and L4 with 20% CSL (200 g·kg⁻¹ fresh matter). The water content was controlled at 65% during fermentation for a period of 45 days. The results showed that the addition of CSL significantly increased the contents of dry matter (DM), crude protein (CP), and lactic acid (LA), while decreasing the pH, neutral detergent fiber (NDF), acid detergent fiber (ADF), and ammonia nitrogen (NH₃-N). Furthermore, the addition of CSL altered the relative abundance of microbial genera. While Pediococcus was the dominant bacterium in the CON group, Lactobacillus became the prevalent species upon the addition of CSL, and its relative abundance increased in accordance with the supplemental amount. These findings suggest that CSL provides a favorable environment for lactic acid bacteria. It is worth noting that CSL addition did not significantly alter the phylum-level bacterial community structure. The dominant bacterial taxa across all treatments were Bacillota, Proteobacteria, and Bacteroidota, with their cumulative relative abundance accounting for over 95%. The rumen degradation of the tested feedstuff was determined using the in situ nylon bag method. Results revealed that incorporating CSL into corncob silage significantly enhanced the effective degradation rates of DM, CP, NDF, and ADF in the rumen of Kazakh sheep. Specifically, the effective degradation rate of DM in the CON group was only 49.10%, which increased to 53.12% following the addition of 20% CSL, along with corresponding improvements in the degradation rates of CP, NDF, and ADF. In summary, as a valuable feed additive, corn steep liquor supports the proliferation of beneficial microorganisms in fermentation systems by supplying essential growth substrates. Additionally, it improves the nutritional balance of corncob feed and further enhances the absorption and utilization of nutrients from this feed by animals. Full article

Making full use of feed nutrients, reducing energy losses and methane emissions, and maximizing production benefits have been ongoing goals of livestock production. Thirty-six healthy Dorper × Thin-tailed Han mutton ewes were divided into six groups using a completely randomized experimental design. A basal diet was provided to the control group, while the experimental group consumed a diet in which 15% was replaced by equal amounts of cottonseed meal (CM), rapeseed meal (RM), distillers dried grains with solubles (DDGS), soybean meal (SM), and fermented soybean meal (FSM). The study demonstrated that SM had the highest protein digestibility, followed by FSM, DDGS, and CM in that order. In terms of net energy, DDGS showed a significantly higher value compared to FSM (p < 0.05). Significantly higher abundances of Lactobacillaceae and Bifidobacteriaceae were observed in the CM group relative to the RM and FSM groups (p < 0.05). The methane emissions that we were most concerned about, whether it was daily emissions or metabolic weight basis, showed the same disparity between the groups, with the RM group having the most, followed in order by FSM, DDGS, and SM groups, and the least by the CM group. We found that the RM group had the highest relative abundance of Methanobrevibacter, followed by the FSM, SM, DDGS, and CM groups in that order, which is similar to the trend of methane emissions from each group. In summary, the highest apparent protein digestibility is SM, and the highest net energy value among these protein feeds is DDGS. RM will produce the most methane. In addition, the source of protein feed in the diet will affect the structural composition of rumen microorganisms. Full article

The growth and development of ruminants are closely linked to the stability and functional capacity of their rumen microbiota. Rumen microbiota transplantation (RMT), which entails the transfer of ruminal microorganisms and their metabolites from healthy donors to recipient animals, has emerged as a promising strategy for modulating host physiology. Accumulating evidence indicates that RMT can substantially influence nutrient digestion, immune function, and overall growth performance. This review synthesizes current knowledge on the mechanisms through which RMT affects ruminant growth and development, with particular attention to its roles in shaping microbial colonization and succession, enhancing rumen fermentation efficiency, and modulating host metabolic pathways. Together, these regulatory processes contribute to improved rumen maturation in young animals and enhanced production performance in adults. In addition, this review critically examines key factors governing the efficacy of RMT, including transplantation procedures, donor microbiota characteristics, and the physiological status of recipient animals. By integrating these insights, the present synthesis provides a conceptual framework to support the precise and effective application of RMT in the sustainable management of healthy ruminant production systems. Full article