Search Results (138)

Modern dairy production has greatly increased milk yield, but high productivity is often accompanied by greater metabolic pressure, particularly during the transition period. Ketosis, fatty liver, and subacute ruminal acidosis are major disorders that limit health, efficiency, and sustainability in high-yielding dairy ruminants. This review examines the rumen microbiota as a central biological interface linking diet, ruminal fermentation, epithelial function, hepatic metabolism, and inflammation. Under homeostatic conditions, the rumen microbiota supports lactation by converting dietary fibre, starch, and nitrogen into volatile fatty acids, microbial protein, and other metabolites required for gluconeogenesis, milk component synthesis, and epithelial maintenance. However, under excessive nutritional or physiological stress, especially high-concentrate feeding and periparturient negative energy balance, this system may shift toward dysbiosis, acid accumulation, lipopolysaccharide release, epithelial barrier impairment, and activation of gut–liver inflammatory pathways. These changes can contribute to the occurrence and interaction of subacute ruminal acidosis, ketosis, and fatty liver. We further summarize key factors affecting rumen microbial stability, including diet structure, host variation, physiological stage, environmental stress, feeding management, and ruminal epithelial volatile fatty acid absorption. Finally, microbiome-oriented strategies, such as gradual dietary transition, nutritional preconditioning, probiotics, postbiotics, functional metabolites, host metabolic support, and epithelial-targeted interventions, are discussed. Maintaining rumen microbial homeostasis should be regarded as a core principle for balancing high milk yield with long-term metabolic health. Future research should move beyond descriptive profiling toward causal validation of host–microbe interactions and the development of microbiome-based early-warning and individualized nutritional management systems. Full article

Efficient utilization of lignocellulosic biomass by the rumen microbiome is critical for improving feed efficiency in ruminants, yet the development of stable, functionally specialized microbial consortia remains limited. This study aimed to assemble substrate-adapted rumen microbial consortia using an ecology-guided enrichment approach. Rumen fluid collected from cannulated Angus × Hereford heifers was sequentially enriched over 10 generations on four substrates with distinct cell wall characteristics: alfalfa, barley straw, carboxymethyl cellulose (CMC), and xylan. Fermentation parameters, including gas production and volatile fatty acids (VFAs), and bacterial community dynamics were analyzed, and selected consortia (alfalfa and xylan) were evaluated for stability following one month of cryopreservation. Across enrichments, total VFA concentrations declined (e.g., xylan: 109.8 mM (G0) to 56.37 mM (G10)), accompanied by reduced gas production and decreased alpha diversity, indicating substrate-driven selection. Distinct functional profiles emerged, including increased propionate in alfalfa consortia, higher acetate in barley straw, lactate–propionate cross-feeding with CMC, and caproate production (6.3 mM at G10) in xylan enrichments associated with Caproiciproducens and Megasphaera. Cryopreserved consortia retained core community structure and fermentation characteristics upon revival. These results demonstrate that substrate-driven enrichment can generate stable, functionally specialized rumen consortia and provide a framework for developing ecologically compatible microbial communities with potential applications in improving rumen fermentation efficiency. Full article

The early-life rumen microbiome is highly dynamic, shaped by dietary transitions and maternal influences. Several dietary additives have been studied during the pre- and post-weaning periods to improve animal welfare, growth performance, and farming efficiencies. This study investigated microbial community assembly and growth performance of lambs provided with a mannan-rich fraction (MRF) supplement, either through maternal supplementation, directly, or via a combination of both. Using metagenomic sequencing and gas chromatography, we found differences in rumen microbial alpha and beta diversity related to both sampling time point and MRF supplementation (p < 0.05). At week 8, lamb microbiomes showed greater variance in their Shannon alpha diversity, with direct MRF supplementation only to the lamb resulting in a significantly greater diversity (p < 0.05). At week 20, combined maternal and lamb supplementation resulted in the highest Shannon diversity and was different compared to all other groups (p < 0.05). Beta diversity analyses combined with differential abundance analyses revealed that microbial community structures are driven by both diet and time, with maternal MRF supplementation associated with enrichment of taxa involved in carbohydrate fermentation and succinate metabolism, including Succiniclasticum ruminis, Succinovibrio dextrinosolvens, and Fibrobacter succinogenes. Generalized linear modeling identified significant associations between microbial alpha diversity metrics and total volatile fatty acids in lambs, particularly butyrate and valerate. Furthermore, at week 8, there was a significant positive correlation between alpha diversity metrics and propionate and valerate. In this study, lambs receiving MRF through maternal and direct supplementation had the highest growth performance, measured as the median average daily gains (kg) and final weights (kg) of lambs. These findings suggest that MRF supplementation, especially when provided both maternally and directly, may influence the lamb rumen microbiome and alter its metabolic potential with potential implications for optimizing early-life nutrition strategies in ruminant production systems. Full article

Background: Antimicrobial resistance (AMR) is a growing global health concern, driven in part by antibiotic use in animal production systems. Despite its relevance, the microbiome and resistome of small ruminant farm environments remain largely underexplored. Methods: In this study, shotgun metagenomics was applied to environmental samples from 46 sheep, goat and mixed-species farms across 14 municipalities in central Portugal. Results: Microbial profiling revealed a well-preserved microbiome with Pseudomonadota, Actinomycetota, Bacteroidota and Bacillota (syn. Proteobacteria, Actinobacteria, Bacteroidetes and Firmicutes respectively) as the most dominant phylum across different farm types. Regarding AMR, a total of 706 unique antimicrobial resistance genes (ARGs), covering 15 antibiotic classes, were detected. Tetracycline, aminoglycoside and macrolide resistance genes dominated across all samples, forming a conserved core resistome. While overall resistome profiles were broadly similar among farm types, significant differences were observed in specific ARG classes, such as pleuromutilin and fosfomycin. Conclusions: These findings highlight small ruminant farm environments as potential reservoirs of clinically relevant ARGs, including WHO highest priority critically important antimicrobial (HPCIA) resistance genes for macrolides (mph(c), erm(f), erm(b)) and fluoroquinolones (qnrD1), as well as critically important antimicrobial (CIA) resistance genes for glycopeptides (vanR-SC, vanR-O) and aminoglycosides (str, aadA), supporting the need to incorporate these environments into surveillance strategies. Full article

Human skin lipids form interconnected pools that support barrier integrity, immune balance, and interactions with the environment. The stratum corneum barrier is built from an ordered mix of ceramides, cholesterol, and long-chain free fatty acids, while sebaceous lipids and their breakdown products shape surface properties and the skin microbiome. Hexadecenoic fatty acids are key at this interface. Palmitoleic acid (cis-9 16:1; 16:1 n−7, POA) is enriched in viable epidermis and remains detectable in stratum corneum lipids, whereas its isomer sapienic acid (cis-6 16:1; 16:1 n−10) predominates in human sebum. Together, they influence membrane organization, lipid fluidity, and antimicrobial defense. This mini-review outlines skin lipid composition and function with a focus on POA and then summarizes experimental and preclinical topical evidence suggesting antimicrobial effects, enhanced lubrication properties, protection from oxidative and ultraviolet B (UVB) injury, and enhanced wound repair. It also reviews early clinical findings from oral POA supplementation trials reporting improved hydration, barrier function, and markers of photo-oxidative aging, with exploratory signals for acne in a multi-nutrient regimen. Major POA sources include sea buckthorn pulp oil, macadamia and avocado oils, selected marine oils, ruminant fats, and emerging fermentation-derived products. Robust mechanistic human studies are still needed to define optimal dosing, formulations, and indications. Full article

Microecological preparations exert beneficial effects on the health of young ruminant animals; however, the mechanism is unclear. As a result, the present study analyzed the effects of yeast cultures on the growth properties, microbiome, and metabolism of weaned lambs. In this study, a total of 20 weaned lambs were randomly, stochastically divided into four teams: the control group (Group A) were fed a basic diet; Group B were fed with Saccharomyces cerevisiae BC strain culture (30 g/head/d); Group C were fed with Kluyveromyces marquez XR4 strain culture (30 g/head/d); Group D were fed with a composite culture of the two yeast strains (30 g/head/d). The study lasted for 40 days, with daily records of lamb feed intake and weight. Lamb feces were collected regularly for metagenomic sequencing and metabolomics analysis. The average daily weight gain and average daily yield of Group D lambs were significantly higher than those of Group A lambs (p < 0.01). The feed utilization rate in the yeast-fed groups was considerably higher than in the control group (p < 0.05), indicating that the addition of yeast crops to lamb feed might improve lamb feed performance. Bacteroides and the mTOR signaling pathway were dramatically enriched in the intestines of weaned lambs in the yeast-culture-fed groups, and their expression levels of ketones and benzoic acid compounds were significantly upregulated. These results indicated that yeast culture had excellent effects on weaned lambs in regulating immunological functioning and the intestinal environment, protecting the enteric mucosal barrier, improving digestion and nutritional absorption, and enhancing antioxidant function. In summary, adding yeast culture to weaned lamb feed can generate a positive effect on its productivity performance and gut health. These findings provide novel insights into promoting the health of young ruminants. Full article

The study investigated differences in ruminal and fecal microbiota composition, fermentation traits, and volatile organic compounds (VOC) in Simmental dairy cows classified as high (HME) or low (LME) methane emitters. Methane emissions from 48 cows were quantified using the Laser Methane Smart portable gas detector. The 12 animals with the highest and lowest emissions were selected and assigned to the HME and LME groups, respectively, balanced for body weight, days in milk, and body condition score. Rumen fluid and fecal samples were analyzed for pH, ammonia, volatile fatty acids (VFA), VOC, and microbiota composition. As expected, CH₄ emissions were significantly higher in HME than in LME cows (22.5 vs. 13.2 g/kg DMI; 16.9 vs. 8.4 g/kg FCM). The neutral detergent fiber digestibility was higher in HME cows (51.4% vs. 47.9%). The valeric acid concentration and the acetate-to-propionate ratio were significantly higher in HME cows (3.53 vs. 3.31). The VOC profiles significantly differed between groups in both feces and rumen fluid. The microbiota analysis revealed a significant difference between groups at the order and genus levels (Bray–Curtis dissimilarity). The Shannon index was higher in LME cows (2.08 vs. 1.95). HME cows exhibited a higher abundance of Methanosphaera and Methanobacteriales. Overall, the results indicate that re-shaping the rumen microbial community can play a key role in reducing methane emissions, strengthening the case for microbiome-driven approaches and offering insights that can support mitigation strategies across dairy production systems. Full article

Ruminant livestock production faces increasing pressure to reduce environmental impacts while maintaining productivity and food security. This comprehensive review examines current strategies and emerging technologies for enhancing environmental sustainability in ruminant systems. The review synthesizes recent advances across four interconnected domains: genetic and genomic approaches for breeding environmentally efficient animals, rumen microbiome manipulation, nutritional strategies for emission reduction, and precision management practices. Specifically, genetic and genomic strategies demonstrate significant potential for long-term sustainability improvements through selective breeding for feed efficiency, methane reduction, and enhanced longevity. Understanding host–microbe interactions and developing targeted interventions have also shown promising effects on optimizing fermentation efficiency and reducing methane production. Key nutritional interventions include dietary optimization strategies that improve feed efficiency, feed additives, and precision feeding systems that minimize nutrient waste. Furthermore, management approaches encompass precision livestock farming technologies including sensor-based monitoring systems, automated feeding platforms, and real-time emission measurement tools that enable data-driven decision making. Integration of these approaches through system-based frameworks offers the greatest potential for achieving substantial environmental improvements while maintaining economic viability. In addition, this review identifies key research gaps including the need for standardized measurement protocols, long-term sustainability assessments, and economic evaluation frameworks. Future directions emphasize the importance of interdisciplinary collaboration, policy support, and technology transfer to accelerate adoption of sustainable practices across diverse production systems. Full article

Rumen microbiota is pivotal for nutrient metabolism and physiological adaptation in ruminants. This study investigated the rumen microbial community, fermentation parameters, and serum biochemistry of three Cervid species—Sika deer (Cervus nippon), Reindeer (Rangifer tarandus), and Milu deer (Elaphurus davidianus) (n = 5/group)—fed an identical diet. Using 16S rRNA sequencing and biochemical analyses, we found that while Bacteroidota, Firmicutes, and Proteobacteria were dominant phyla across species. Sika deer and Milu deer exhibited significantly higher microbial diversity and abundance of carbohydrate-digesting genera (e.g., Butyrivibrio, Saccharofermentans), and pathways of carbohydrate digestion and absorption, starch and sucrose metabolism compared to Reindeer. Conversely, Reindeer showed increased abundances of Lachnospiraceae ND3007 and butyrate metabolism pathway, and significantly elevated rumen volatile fatty acid concentrations, particularly acetate and butyrate. Serum profiling revealed that Milu deer had significantly higher lipid levels (CHO, TG, LDL-C) but lower total protein and AST levels compared to other species. Notably, WGCNA linked these blood lipid traits to host genes enriched in PI3K-Akt, MAPK, and bile secretion pathways. These findings demonstrate distinct species-specific rumen fermentation patterns and host metabolic adaptations, suggesting a coordinated regulation between the rumen microbiome and host genetics in Cervid. Full article

This study examined the effect of dandelion extracts on the ruminal microbiota, metabolome, and inflammatory response in dairy goats fed a high-concentrate diet. Eighteen Guanzhong dairy goats were assigned to three groups: low-concentrate diet group (L group, F:C = 60:40), high-concentrate diet group (H group, F:C = 35:65), and dandelion group (D) with 1% dandelion extracts based on the H group. Over six weeks, milk, blood, and ruminal fluid were collected to analyze pH, volatile fatty acids (VFAs), inflammatory markers, microbiome, and metabolome. Feed intake was significantly higher in the H and D groups than in the L group. Ruminal pH decreased in the H group, acetate was significantly higher in the L and D groups, and serum IgA was higher in D group. Bacteroidetes and Firmicutes were dominant rumen phyla, and dandelion supplementation significantly increased Proteobacteria. Prevotella abundance was enriched in the L and D groups and showed a positive correlation with acetate. Dandelion extracts also increased the production of trans-3-Hydroxy-L-proline and 7-Ethyl-5,6-dihydro-1,4-dimethylazulene in the rumen while improving amino acid and lipid metabolism. Overall, supplementation of dandelion extracts positively influenced rumen microbiota, enhanced production of beneficial metabolites, and positively influenced immune function in dairy goats fed high-concentrate diet. Full article

High-yielding dairy cows suffer from a high metabolic load and oxidative stress, which lead to systemic inflammation and metabolic disorders, increasing the susceptibility of these cows to various production diseases. Dihydromyricetin (DMY) has demonstrated potent antioxidant and anti-inflammatory physiological functions; however, research into its application in ruminants remains limited. This study investigated whether DMY supplementation is associated with the maintenance of metabolic homeostasis through the regulation of gut microbiota and metabolite profiles. A total of 14 mid-lactation Holstein dairy cows were randomly divided into two groups (n = 7 per group) and supplemented with DMY at 0 or 0.05% in their basal diet for 60 consecutive days. The effects of DMY on the blood biochemical indicators and the antioxidant capacity of the dairy cows were then determined. Alterations to the gut microbiome and the fecal and plasma metabolome were analyzed through 16S rDNA sequencing and untargeted metabolomics. The results showed that DMY significantly improved the activity of serum glutathione peroxidase (GSH-Px) and presented a trend of increasing the total antioxidant capacity (T-AOC). The abundance of multiple fiber-degrading and beneficial commensal bacteria in the gut, including Fibrobacter_succinogenes, Ruminococcus_albus, and Turicibacter, was significantly elevated by the DMY intervention, accompanied by the upregulation of 8,11,14-eicosatrienoic acid, myricetin, dihydro-3-coumaric acid, PGE1, L-leucine, nicotinuric acid, pantothenic acid, and pyruvate in the feces and plasma. Moreover, DMY supplementation notably reduced the abundance of potential pathogenic microbes, such as Chloroflexi, Deltaproteobacteria, RFP12, and Succinivibrio, and downregulated the levels of 12-hydroxydodecanoic acid, 12,13-DHOME (12,13-dihydroxy-9Z-octadecenoic acid), 16-hydroxyhexadecanoic acid, niacin, and glycerol 3-phosphate. These differential metabolites were principally enriched in the mTOR signaling pathway; pantothenate, nicotinate, and thiamine metabolism; glutathione metabolism; and glycolysis/gluconeogenesis. In summary, dietary supplementation with DMY increased the abundance of intestinal fiber-degrading bacteria and multiple metabolites with known anti-inflammatory and antioxidant properties in the feces and plasma, and was associated with alterations in metabolic pathways involving B-vitamins, amino acids, and glutathione. This suggests a potential role for DMY in supporting metabolic homeostasis in dairy cows. Full article

The gastrointestinal microbiota of ruminants constitutes a complex invisible organ, which converts plant fibers into volatile fatty acids (VFAs) and microbial protein through fermentation, serving as the primary energy and protein sources for the host. While substantial progress has been made in characterizing this system, critical gaps remain in understanding causal mechanisms and translating knowledge into scalable interventions. This review systematically synthesizes current knowledge on the composition, function, and metabolite profiles of gastrointestinal microbial communities in ruminants, with emphasis on interaction mechanisms, methodological advances, and intervention strategies. We highlight persistent challenges, including the uncultured majority of microbes, causal inference limitations, and translational bottlenecks. The review further evaluates strategies for targeted microbiome modulation aimed at improving production performance and reducing environmental emissions. Finally, we propose integrated research priorities for developing efficient, low-carbon, and sustainable ruminant production systems. Full article

Probiotics have emerged as gut modulators, capable of restructuring microbial communities to enhance animal health and performance. This review synthesizes peer-reviewed studies published between 2015 and 2025, retrieved from Scopus, Web of Science, and Google Scholar. It encompasses both ruminant and monogastric species to evaluate the effects of probiotic supplementation under diverse production environments. Evidence indicates that diet, age, host genetics, and management practices strongly influence gut microbiome composition and function, explaining the context-dependent nature of probiotic efficacy. These interventions improve growth performance, feed efficiency, gut morphology, pathogen resistance, and systemic immune parameters, supporting their potential as sustainable alternatives to antibiotic growth promoters. However, responses vary and are context-dependent, based on differences in strain specificity, dosage, host physiology, and environmental stress. By explaining how probiotic-mediated modulation translates into improved productivity, reduced antimicrobial dependence, and greater resilience in real-world farming systems, this review highlights their practical value for modern livestock production. Future research should focus on field-based validation, multi-omics approaches to resolve host–microbiota–probiotic interactions, and long-term assessments of animal health, productivity, and environmental impacts. Strategic deployment of probiotics, combined with scalable delivery technologies and regulatory alignment, can enhance resilience, sustainability, and efficiency in livestock production systems. Full article

Yeast culture (YC) is a microbial product that enhances ruminal fiber breakdown and improves nutrient digestion and utilization. Our previous research showed that oxalic acid (OA) is a crucial metabolite in YC that enhances rumen function. This study aimed to investigate the effects of YC, OA, and their combination (YO) on rumen function, growth, and fattening in sheep. Twenty lambs were divided into 4 groups (ctrl, YC, OA, and YO; n = 5 each) and fed a diet supplemented with 2 levels of YC and 2 doses of OA for 60 days in a 2 × 2 factorial design. Growth and fattening performance, rumen microbiome analysis, serum indices and anti-oxidant levels, and metabolomic profiling were performed. Individual supplementation with YC and OA significantly increased the digestibility of dry matter (DM), organic matter (OM), and crude protein (CP) (p < 0.001); neutral detergent fiber (NDF) (p < 0.05); and acid detergent fiber (ADF) (p < 0.001) and their interaction significantly increased dry matter intake (DMI) (p = 0.05). Serum IgA and IgM levels were higher in the supplemented groups (p < 0.05). Serum calcium levels were higher in the OA and YO groups (p < 0.001). The supplemented groups showed significantly higher growth hormone and superoxide dismutase levels (p < 0.05). The longissimus dorsi muscle had higher levels of iron in the OA and YO groups; zinc in the OA, YO, and YC groups (p < 0.01); and selenium in the YC group (p < 0.05). The OA group had a higher total antioxidant capacity. All supplemented groups showed higher bacterial richness and diversity. Ruminococcus, Succinivibrio, and Fibrobacter were positively correlated with the fermentation and digestibility parameters. The supplementation also altered metabolite levels and types in key physiological pathways. In conclusion, this supplementation improved bacterial composition, nutrient digestibility, weight gain, carcass weight and quality, serum indices, antioxidant levels and metabolomic profiles. This suggests potential for the development of dietary supplements for ruminants. Full article

This narrative review aims to summarize, synthesize, and organize current knowledge on the adaptation of sheep and goats to stressful environments and to discuss how these adaptations contribute to food security in vulnerable communities. A structured search of Web of Science, Scopus, PubMed, and Google Scholar was conducted using combinations of terms related to sheep and goats, harsh environments (e.g., arid and semi-arid regions, heat stress, water restriction, poor-quality forage), and adaptation or resilience, combined with Boolean operators. A total of 1718 research publications were found, of which 86 were retained as the most relevant because they provided direct and detailed evidence on anatomical, physiological, digestive–microbiome, behavioral, and genomic adaptations of sheep and goats to stressful environments. The selected studies describe a wide range of phenotypic and integumentary traits, thermoregulatory and endocrine responses, digestive and microbial adjustments, behavioral strategies, and genomic signatures that, together, allow small ruminants to maintain basic functions, reproduction, and production under conditions of climatic and nutritional stress. Evidence from these studies also highlights how adaptive traits support herd productivity, economic stability of households, and the sustainable use of natural resources in regions where climatic variability and resource scarcity are common. Overall, the synthesis presented here underscores the importance of conserving and strategically using locally adapted sheep and goat breeds, incorporating resilience-related traits into breeding and management programs, and prioritizing further research on genomic, microbiome, and epigenetic mechanisms that underpin adaptation to harsh environments. Full article