Search Results (53)

Understanding the function of enzymes before their use as additives in ruminant diets is essential for achieving sustainable and efficient agricultural practices. Ruminants such as cattle, sheep, and goats are vital for global food production because of their ability to convert fibrous plant materials into high-quality proteins through enteric fermentation. Various datasets were carefully selected from four scientific databases: Science Direct, Scopus, PubMed, and Google Scholar. The rigorous Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) protocol was employed to ensure the eligibility of the selected articles used in the analysis. A systematic review showed that the administration of various types of enzymes can increase dry (DMD) and organic (OMD) matter, neutral (NDFD), and acid (ADFD) detergent fibre, and crude protein (CPD) digestibility in both in vitro and in vivo tests in individual studies. However, the pooled meta-analysis indicated that their overall effect on CPD was not significant (p > 0.05). The OpenMEE approach was used to calculate the effect size (Hedges’ g) for each experimental unit for various parameters. Across enzyme types and doses in the meta-analysis, the administration of enzymes did not have any significant effect (p > 0.05) on DMI, OMI, and CPD, but it did have a significant effect (p < 0.05) on DMD, OMD, ADFD, NDFD, pH and gas production at 24, 48, and 72 h, as assessed by in vitro experiments. Ruminant in vivo studies indicated that the administration of enzymes has significant impacts (p < 0.05) on digestibility parameters (DMD, OMD, NDFD, ADFD), milk production, milk lactose content, acetate, and propionate, but it had non-significant impacts on milk protein and rumen total volatile fatty acids and acetate: propionate ratio. Full article

Introduction: Eravacycline is a new fluorocycline antibiotic with a broad spectrum of antimicrobial activity approved for the treatment of patients with complicated intra-abdominal infections. This systematic review aimed to evaluate the published data on the resistance of Gram-negative bacterial isolates to eravacycline. Methods: We identified relevant publications by systematically searching Embase, PubMed, Scopus, and Web of Science from their inception to 29 August 2025. Published antimicrobial resistance breakpoints of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the US Food and Drug Administration (FDA) were used. Results: Data on 59,922 Gram-negative bacterial clinical isolates were retrieved from 68 articles after the screening of 283 potentially relevant studies. The resistance of consecutive (non-selected) Escherichia coli ranged from 0.9% to 9.6%. The MIC₅₀ values of eravacycline were ≤0.5 mg/L for Acinetobacter baumannii isolates, including carbapenem-resistant A. baumannii, in the majority of studies. The proportions of resistance were higher among other lactose non-fermenting Gram-negative bacterial isolates, especially Pseudomonas aeruginosa, as well as among selected E. coli with advanced patterns of antimicrobial resistance. Conclusions: The evaluated data support the adequate antimicrobial activity of eravacycline against most Gram-negative bacterial clinical isolates. However, in vitro antimicrobial susceptibility testing and modern molecular diagnostic tests, including those that examine mechanisms of resistance, are helpful for the appropriate use of eravacycline in clinical practice. Full article

This study aimed to evaluate the supplementation of aqueous extract of Moringa oleifera (AEMO) as a natural ruminal modulator to improve the lactation performance of ewes. The AEMO was prepared by chopping Moringa oleifera leaves and diluting them in distilled water (163.3 g DM/L). Twelve ewes were used in a replicated 3 × 3 Latin square, with periods of 14 days (assessments on the last five days of each period). Treatments were as follows: 20 mL of water as Control, 20 mL of AEMO (20-AEMO), and 40 mL of AEMO (40-AEMO). Ewes were milked twice a day (7:30 a.m. and 2:30 p.m.). Diet corresponds to grain mix (at 3% of BW) and hay ad libitum. We determined the intake, digestibility, fermentative measurements, metabolic measurements, and milk production and composition. Intake and digestibility were not affected by AEMO. Milk yield and the concentrations of fat, protein, and lactose were numerically lower in ewes supplemented with 20-AEMO. A linear decrease in milk protein yield was observed when the highest extract level (40-AEMO) was used. Ruminal pH did not differ among treatments; however, there was a tendency for reduced acetate and increased propionate concentrations, which corresponded with a non-significant numerical decrease in methane estimates in 40-AEMO group. Blood and urinary parameters were not affected by AEMO supplementation. Inclusion of Moringa extracts as an additive in lactating ewes diet does not affect intake and nutrient digestibility, but tends to affect ruminal fermentation and microbial synthesis, with possible changes in methane emission estimation, and impair milk protein production. Therefore, we recommend studies with different extract concentrations to investigate possible effects on rumen fermentation and the synthesis of milk compounds. Full article

Streptococcus thermophilus is a Gram-positive, homofermentative lactic acid bacterium classified within the Firmicutes phylum, recognized for its probiotic properties and significant role in promoting human health. This review consolidates existing understanding of its metabolic pathways, functional metabolites, and diverse applications, highlighting evidence-based insights to enhance scientific integrity. S. thermophilus predominantly ferments lactose through the Embden-Meyerhof-Parnas pathway, resulting in L(+)-lactic acid as the primary end-product, along with secondary metabolites including acetic acid, formic acid, and pyruvate derivatives. Exopolysaccharides (EPS) are composed of repeating units of glucose, galactose, rhamnose, and N-acetylgalactosamine. They display strain-specific molecular weights ranging from 10 to 2000 kDa and contribute to the viscosity of fermented products, while also providing antioxidant and immunomodulatory benefits. Aromatic compounds such as acetaldehyde and phenylacetic acid are products of amino acid catabolism and carbohydrate metabolism, playing a significant role in the sensory characteristics observed in dairy fermentations. Bacteriocins, such as thermophilins (e.g., Thermophilin 13, 110), exhibit extensive antimicrobial efficacy against pathogens including Listeria monocytogenes and Bacillus cereus. Their activity is modulated by quorum-sensing mechanisms that involve the blp gene cluster, and they possess significant stability under heat and pH variations, making them suitable for biopreservation applications. In food applications, S. thermophilus functions as a Generally Recognized as Safe (GRAS) starter culture in the production of yogurt and cheese, working in conjunction with Lactobacillus delbrueckii subsp. bulgaricus to enhance acidification and improve texture. Specific strains have been identified to mitigate lactose intolerance, antibiotic-related diarrhea, and inflammatory bowel diseases through the modulation of gut microbiota, the production of short-chain fatty acids, and the inhibition of Helicobacter pylori. The genome, characterized by a G + C content of approximately 37 mol%, facilitates advancements in Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas technology and heterologous protein expression, with applications extending to non-dairy fermentations and the development of postbiotics. This review emphasizes the adaptability of S. thermophilus, showcasing the variability among strains and the necessity for thorough preclinical and clinical validation to fully utilize its potential in health, sustainable agriculture, and innovation. It also addresses challenges such as susceptibility to bacteriophages and limitations in proteolytic activity. Full article

Nowadays, the consumption of “free from” foods by non-specific consumers is increasing, partly due to a misperception of labels that make them seem healthier. These foods are formulated for consumers with allergies or diseases that limit their diet, and it is not known if there are more benefits than risks for healthy consumers. For example, there is no work investigating the interaction between lactose-free milk and the colonic microbiome of healthy individuals. To focus on the potential modulation of gut microbiota of healthy subjects by lactose-free milk, we performed an in vitro simulation of digestion and fermentation, integrating microbiomics and metabolomics approaches to study changes in gut microbiota populations and metabolite production. Results indicated that lactose-free and lactose-containing milk differently modulated colonic microbiota based on several microbiological indicators, including the reduction in Bifidobacteriaceae (approximately more than two times) and Lactobacillales and the reduction in the beneficial production of microbial compounds (approximately six times less acetic acid and two times less butanoic acid). Such features suggest that lactose-free milk increases the risk of dysbiosis in healthy subjects. Our work identifies the drivers of this dysbiosis among hundreds of molecules and microbes of the gut microbiota, assigning specific names and ecological niches for the first time. It employs an in vitro model, which represents a new standard for sustainable research and improves translatability. Our findings support the European Society for Clinical Nutrition and Metabolism (ESPEN) guidelines, which do not recommend the routine consumption of lactose-free diets in the absence of diagnosed intolerance. Full article

Cefepime-enmetazobactam is a novel β-lactam/β-lactamase inhibitor combination showing good activity against multidrug-resistant (MDR) Gram-negative bacteria producing a variety of β-lactamases. In this systematic review, we aimed to evaluate the available data on resistance to this drug. We performed a thorough search of four databases (Embase, PubMed, Scopus, and Web of Science), as well as backward citation searching, to identify studies containing data on resistance to cefepime-enmetazobactam. The data were extracted and analyzed according to the breakpoints established by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Food and Drug Administration (FDA), or the specific breakpoints reported by the authors of the respective studies. Analysis based on the type of lactamases produced by the isolates was also performed. Ten studies reported in vitro susceptibility testing and mechanisms of antimicrobial resistance. The total number of isolates was 15,408. The activity of cefepime-enmetazobactam against β-lactamase-producing isolates was variable. The resistance of the studied extended-spectrum β-lactamase (ESBL)-producing and ampicillin C β-lactamase (AmpC)-producing isolates was low (0–2.8% and 0%, respectively). The resistance was higher among oxacillinase-48 β-lactamase (OXA-48)-producing and Klebsiella pneumoniae carbapenemase (KPC)-producing isolates (3.4–13.2% and 36.7–57.8%, respectively). High resistance was noted among metallo-β-^lactamase (MBL)-producing isolates (reaching 87.5% in one study), especially those producing New Delhi metallo-β-lactamase (NDM) and Verona integron-encoded metallo-β-lactamase (VIM), which had the highest rates of resistance. The high activity of cefepime-enmetazobactam against Enterobacterales and selected lactose non-fermenting Gram-negative pathogens, including ESBL-producing and AmpC-producing isolates, makes it a potential carbapenem-sparing agent. The drug should be used after in vitro antimicrobial susceptibility testing in patients with infections caused by OXA-48, KPC, and MBL-producing isolates. Full article

Irritable bowel syndrome (IBS) is a gut–brain axis chronic disorder, characterized by recurrent abdominal pain and altered bowel habits in the absence of organic pathology. Nutrition plays a central role in symptom management, yet no single dietary strategy has demonstrated universal effectiveness. This narrative review critically evaluates current nutritional approaches to IBS. The low-Fermentable Oligo-, Di-, Mono-saccharides and Polyols (FODMAP) diet is the most extensively studied and provides short-term symptom relief, but its long-term effects on microbiota diversity remain concerning. The Mediterranean diet, due to its anti-inflammatory and prebiotic properties, offers a sustainable, microbiota-friendly option; however, it has specific limitations in the context of IBS, particularly due to the adverse effects of certain FODMAP-rich foods. A gluten-free diet may benefit individuals with suspected non-celiac gluten sensitivity, although improvements are often attributed to fructan restriction and placebo and nocebo effects. Lactose-free diets are effective in patients with documented lactose intolerance, while a high-soluble-fiber diet is beneficial for constipation-predominant IBS. IgG-based elimination diets are emerging but remain controversial and require further validation. In this review, we present the 10 dietary commandments for IBS, pragmatic and easily retained recommendations. It advocates a personalized, flexible, and multidisciplinary management approach, avoiding rigidity and standardized protocols, with the aim of optimizing adherence, symptom mitigation, and health-related quality of life. Future research should aim to evaluate, in real-world clinical settings, the impact and applicability of the 10 dietary commandments for IBS in terms of symptom improvement and quality of life Full article

One of the world’s most sustainable solutions is to replace fossil-based polymers with biopolymers. The production of xanthan gum can be optimized using various renewable and cost-effective raw materials, which is a key focus in industrial biotechnology. Xanthan gum is a bioengineered thickening, stabilizing, and emulsifying agent. It has unique properties for use in many industries (food, biotechnology, petrochemicals, agricultural, cosmetics, wastewater treatment) and medical applications. It is tasteless, environmentally safe, non-toxic, and biodegradable. The biotechnological production of xanthan gum depends on several factors: bacterial strain development, culture medium preparation, carbon sources, fermentation parameters and modes, pH, temperature, recovery, purification, and quality control regulations. Bio-innovative strategies have been developed to optimize the production of xanthan gum. A variety of carbon and nitrogen sources, as well as alternative renewable sources, have been used in the production of xanthan gum. The aim of the present study was to optimize the xanthan gum yield using Xanthomonas campestris bacteria and different carbon (D-glucose, D-sorbitol, lactose, sucrose, D-mannitol, D-fructose, erythritol, coconut palm sugar, L-arabinose, unrefined cane sugar), various nitrogen (bacterial peptone, casein peptone, L-glutamic acid, L-arginine, L-methionine, L-tryptophan, malt extract, meat extract, L-phenylalanine, soy peptone) and alternative carbon (orange peels, tangerine peels, lemon peels, avocado peels, melon peels, apple peels, cellulose, xylose, xylitol) sources. The xanthan gum samples were analyzed using antioxidant methods. Our study showed that using L-glutamic acid as the carbon source for 72 h of bacterial fermentation of Xanthomonas campestris resulted in the highest xanthan gum yield: 32.34 g/L. However, using renewable resources, we achieved a very high concentration of xanthan gum in just 24 h of fermentation. According to the reducing power and DPPH methods, the highest antioxidant activities were measured for xanthan gum whose biosynthesis was based on renewable resources. Xanthan gum structures have been verified by FT-IR and ¹H NMR analysis. The sustainable biotechnology study has the advantage of increasing the sustainable production of xanthan gum by using renewable alternative resources compared to other production processes. Xanthan gum continues to be a valuable biopolymer with a wide range of industrial applications while promoting environmentally friendly production practices. Full article

Consumer demand for plant-based functional foods, especially probiotic beverages, has increased due to their health benefits and suitability as dairy-free alternatives. This study assessed, through a factorial combination, the stability of plant-based extracts (avocado, ginger, and tropical) individually inoculated with three commercial Lactobacillus strains (L. casei, L. plantarum, L. reuteri) and stored under refrigerated conditions during both primary (PSL) and secondary shelf life (SSL). Product shelf life was defined by probiotic viability, considering the functional threshold (≥6 log CFU/mL), which was maintained across all formulations throughout the storage period. Physicochemical parameters, including pH, titratable acidity, and colour, as well as volatile profile, remained stable, with only minor variations depending on the matrix and bacterial strain. Sensory evaluations (triangle and acceptability tests) confirmed that the probiotic juices were acceptable to consumers. Overall, the results demonstrate the feasibility of producing non-fermented, plant-based probiotic beverages that retain their functional properties and meet consumer sensory expectations, offering a promising alternative for vegan and lactose-intolerant individuals. Full article

Fermenting fruit and vegetable juices with probiotic bacteria is becoming a popular way to create functional drinks, offering an alternative to traditional dairy-based probiotic products. These plant-based juices are naturally rich in nutrients that help support the growth and activity of various probiotic strains. They also meet the rising demand for lactose-free, vegan, and clean-label options. This review looks at the key microbiological, nutritional, and sensory aspects of probiotic fermentation in juice. Common probiotic groups like Lactobacillus, Bifidobacterium, Lactococcus, Bacillus, and Streptococcus show different abilities to adapt to juice environments, affecting properties such as antioxidant levels, shelf life, and taste. The review also explores how factors like pH, sugar levels, heating, and storage can influence fermentation results. New non-thermal processing methods that help maintain probiotic survival are also discussed. Since fermented juices can sometimes develop off-flavors, this paper looks at ways to improve their taste and overall consumer appeal. Finally, future directions are suggested, including personalized nutrition, synbiotic products, and advanced encapsulation technologies. Overall, probiotic fermentation of fruit and vegetable juices shows strong potential for developing a new generation of healthy and appealing functional foods. Full article

Brucella intermedia, a gram-negative, non-lactose-fermenting, aerobic, rod-shaped bacterium, is found in environmental sources (e.g., soil and water). In 2020, Ochrobactrum was reclassified as Brucella. We conducted a genomic analysis of B. intermedia from hospital wastewater samples in western Ghana. A hybrid genome assembly was constructed integrating short-read data from DNA Nanoball sequencing with long-read sequences generated by Oxford Nanopore MinION technology. Identification and antimicrobial susceptibility profiles were determined using MicroScan autoSCAN-4 based on Clinical and Laboratory Standard Institute documents. ResFinder and CARD Resistance Gene Identifier (RGI) were used to identify antimicrobial resistance (AMR) genes, and BLAST and VFDB datasets were used to identify virulence factor genes. The complete genome had two chromosomes, no plasmid, and a high average nucleotide identity value (98.05%) with B. intermedia. Resistance to trimethoprim-sulfamethoxazole was revealed, the first report in this species. CARD RGI revealed the presence of AMR genes, including ANT(9)-Ic and adeF. Local BLAST analysis revealed Cgs, a B. melitensis virulence factor. B. intermedia is an opportunistic human pathogen clinically isolated several times, suggesting the importance of accurately identifying multidrug resistance. B. intermedia may possess virulence factors similar to those of B. melitensis. Further study is needed to fully elucidate its pathogenesis. Full article

This study examines the fermentation performance of featured bacteria (Lactobacillus acidophilus-ATCC-4356, Lactobacillus helveticus-ATCC-15009, Lactobacillus delbrueckii subsp. bulgaricus-ATCC-11842, Lacticaseibacillus casei-ATCC-393, Streptococcus thermophilus-ATCC-19258 (ST), and Bifidobacterium bifidum-ATCC-29521 (BB)) used in fermented dairy products and their impact on product quality. The main focus is on evaluating the metabolic activities, organic acid production, viscosity values, and sensory properties of probiotic strains such as L. acidophilus, L. bulgaricus, L. casei, L. helveticus, B. bifidum, and S. thermophilus. The strains were activated in a sterile milk medium and incubated until they reached a pH of 4.6. Then, pH, microbial enumeration, organic acid, sugar composition, vitamins A, D, E, K1, and K2 (menaquinone-7), and viscosity values were measured in the bacteria. Organic acid, sugar composition, and vitamins A, D, E, K1, and K2 (menaquinone-7) were analyzed with the HPLC method. Additionally, sensory analyses were performed, and volatile compounds were examined. L. casei demonstrated superiority in lactic acid production, while L. helveticus showed high lactose consumption. L. bulgaricus stood out in galactose metabolism. The highest viscosity was observed in products produced by B. bifidum. Differences in viscosity were attributed to exopolysaccharide (EPS) production and acid production capacity. A total of 62 volatile compounds were identified, with the highest levels of aromatic components found in products containing B. bifidum. The most preferred product, based on panel evaluations, was the fermented dairy product produced with L. acidophilus. As for aroma profiles, it was determined that the phenethyl alcohol, 3-methyl-1 butanol, and ethanol compounds are associated with B. bifidum, the hexanoic acid and 2-methylbutanal compounds are associated with the L. acidophilus, the hexanoic acid, 2-methylbutanal, 2-furanmethanol, and acetaldehyde compounds are associated with the L. bulgaricus, and the hexanoic acid, 2-methylbutanal, 2-heptanone, acetoin, and d-limonene are associated with the L. casei. On the other hand, the L. helveticus strain is associated with the hexanoic acid, 2-methylbutanal, and 2-heptanone, and the S. termophilus strain is associated with the hexanoic acid, hexanol, acetoin, 2,3-pentanedione, 1-butanol, and 3-methyl-2-butanone volatile aroma compounds. The determination of fat-soluble vitamins is particularly important for vitamin K1 and vitamin K2. In this study, the bacterial sources of these vitamins were compared for the first time. The menaquinone-7 production by L. helveticus was determined to be the highest at 0.048 µg/mL. The unique metabolic capacities of these prominent cultures have been revealed to play an important role in determining the aroma, organic acid content, viscosity, and overall quality of the products as a whole. Therefore, the findings of this study will provide the right strain selection for a fermented dairy product or a different non-dairy-based fermented product according to the desired functional properties. It also provides a preliminary guide for inoculation in the right ratios as an adjunct culture or co-culture for a desired property. Full article

Background: Weissella confusa is a member of the lactic acid bacterium group commonly found in many salt-fermented foods. Strains of W. confusa isolated from high-salinity environments have been shown to tolerate salt stress to some extent. However, the specific responses and mechanisms of W. confusa under salt stress are not fully understood. Methods: To study the effect of NaCl stress on W. confusa, growth performance and metabolite profiles of the strains were compared between a NaCl-free group and a 35% NaCl-treated group. Growth performance was assessed by measuring viable cell counts and examining the cells using scanning electron microscopy (SEM). Intracellular and extracellular metabolites were analyzed by non-targeted metabolomics based on liquid chromatography-mass spectrometry (LC-MS). Results: It was found that the viable cell count of W. confusa decreased with increasing salinity, and cells could survive even in saturated saline (35%) medium for 24 h. When exposed to 35% NaCl, W. confusa cells exhibited surface pores and protein leakage. Based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, 42 different metabolites were identified in the cells and 18 different metabolites in the culture medium. These different metabolites were mainly involved in amino acid metabolism, carbohydrate metabolism, and nucleotide metabolism. In addition, salt-exposed cells exhibited higher levels of intracellular ectoine and lactose, whose precursors, such as aspartate, L-2,4-diaminobutanoate, and galactinol, were reduced in the culture medium. Conclusions: This study provides insight into the metabolic responses of W. confusa under salt stress, revealing its ability to maintain viability and alter metabolism in response to high NaCl concentrations. Key metabolites such as ectoine and lactose, as well as changes in amino acid and nucleotide metabolism, may contribute to its tolerance to salt. These findings may improve our understanding of the bacterium’s survival mechanisms and have potential applications in food fermentation and biotechnology. Full article

Growing concerns regarding antibiotic use in livestock, due to antibiotic resistance and potential human transmission, have led to increased interest in herbs and their derivatives, including essential oils, which possess antimicrobial properties that may enhance overall productivity and serve as a strategy for methane mitigation. The objective of this meta-analysis was to investigate the effects of adding oregano to the diet in different forms (essential oils, plant materials, or leaves) on the dry matter intake (DMI), milk yield (MY), milk components, nutrient digestibility, ruminal fermentation parameters, and methane (CH₄) emissions of dairy cows. A literature search was conducted to identify papers published from 2000 to 2023. Effect size for all outcomes was reported as a standardized means difference (SMD) and raw means difference with 95% confidence intervals. Heterogeneity was determined using the Q test and I² statistic. The results of the meta-analysis indicated that adding oregano had no effect on DMI (SMD = 0.081; p = 0.507) and MY (SMD = 0.060; p = 0.665). Milk fat percentage, milk protein percentage, and milk lactose percentage were not affected by oregano. The addition of oregano to the diet significantly decreased dry matter digestibility (SMD = −0.502; p = 0.013), crude protein digestibility (SMD = −0.374; p = 0.040), and neutral detergent fiber digestibility (SMD = −0.505; p = 0.014). Ruminal pH (SMD = −0.122; p = 0.411), total volatile fatty acids concentration (SMD = −0.038; p = 0.798), acetate (SMD = −0.046; p = 0.757), propionate (SMD = 0.007; p = 0.960), and butyrate (SMD = 0.037; p = 0.801) proportion were not affected by oregano. The addition of oregano to the diet tended to decrease CH₄/DMI (SMD = −0.275; p = 0.095) but did not affect CH₄ production (SMD = −0.156; p = 0.282). Heterogeneity (Q and I²) was non-significant for all parameters. We conclude that the inclusion of oregano in various forms (essential oils, plant materials, or leaves) in the diet of dairy cows reduces nutrient digestibility but does not significantly affect DMI, MY, milk components, ruminal fermentation parameters, or CH₄ production. Future research should focus on optimizing the dosage of oregano (both EOs and plant materials) and exploring the impact of its form on lactation, nutrient digestibility, ruminal fermentation, and CH₄ emissions in dairy cows. Full article

This study aimed to evaluate the effects of dietary supplementation with capsaicin (CAP) on productive performance, milk composition, nutrient digestibility, ruminal fermentation, and serum metabolites of dairy cows using a meta-analytical approach. The database included 13 studies, from which the response variables of interest were obtained. Data were analyzed using a random effects model, and results were expressed as weighted mean differences between treatments supplemented with and without CAP. Dietary supplementation with CAP increased (p < 0.05) dry matter intake, milk yield, feed efficiency, milk fat yield, and milk fat content. However, CAP supplementation did not affect (p > 0.05) milk protein and lactose yield, milk urea nitrogen, or milk somatic cell count. Greater (p < 0.05) apparent digestibility of dry matter and crude protein was observed in response to the dietary inclusion of CAP. Likewise, supplementation with CAP increased (p < 0.05) the rumen concentration of total volatile fatty acids. In contrast, CAP supplementation did not affect (p > 0.05) ruminal pH or the ruminal concentration of ammonia nitrogen, acetate, propionate, and butyrate. In blood serum, CAP supplementation increased (p < 0.05) the glucose concentration and decreased (p < 0.05) the concentration of non-esterified fatty acids. However, CAP supplementation did not affect (p > 0.05) the serum concentration of urea and beta-hydroxybutyrate. In conclusion, capsaicin can be used as a dietary additive to improve the productive performance, milk composition, and nutrient digestibility in dairy cows and, at the same time, improve the ruminal concentration of total volatile fatty acids and serum levels of glucose and non-esterified fatty acids. Full article