Essential oil mixture on rumen fermentation and microbial community - an in vitro study

Rumen microbiota succession throughout the perinatal period and its association with postpartum production traits in dairy cows: A review

The transition period for dairy cows usually refers to the 3 weeks pre-calving to the 3 weeks post-calving. During this period, dairy cows undergo metabolic and physiological adaptations because of their susceptibility to metabolic and infectious diseases. Poor feeding management under these circumstances may adversely affect the health and subsequent production performance of the cows. Owing to long-term adaptation and evolution, the rumen has become a unique ecosystem inhabited by a complex microbial community closely associated with its natural host. Dietary components are metabolized by the rumen microbiota, and volatile fatty acids and microbial protein products can be used as precursor substances for synthesizing meat and milk components. The successful transition of perinatal dairy cows includes changes in diet, physiology, and the rumen microbiota. Rumen microbial profiles have been confirmed to be heritable and repairable; however, adverse circumstances affect rumen microbial composition, host digestion and metabolism, as well as postpartum production traits of dairy cows for a certain period. Preliminary evidence indicates a close relationship between the rumen microbiota and animal performance. Therefore, changes in rumen microbes during the transition period and the intrinsic links between the microbiota and host postpartum phenotypic traits need to be better understood to optimize production performance in ruminants.

Combination of Phytoactives in the Diet of Lactating Jersey Cows: Effects on Productive Efficiency, Milk Composition and Quality, Ruminal Environment, and Animal Health

This study's objective was to evaluate whether adding a combination of phytoactive (microencapsulated essential oils, minerals, turmeric extract, tannin, prebiotic, and probiotic) to the feed of lactating Jersey cows positively affects the production, composition, and quality of milk, rumen environment, and animal health. Fourteen Jersey cows were divided into two groups (control and phytogenic) for an experiment with two lactation phases of 45 days each (early lactation and mid-lactation). During the experiment, milk production was higher at various times in cows that consumed phytoactive, and these animals had the best feed efficiency. In mid-lactation, phytoactive intake increased nutrient digestibility. The number of lymphocytes in the blood is reduced when cows consume phytoactive substances. Globulin levels increased in these cows fed with the additive, which may be related to a higher concentration of immunoglobulins, especially IgA. Cows fed phytoactives had lower ceruloplasmin and haptoglobin concentrations. Lower serum lipid peroxidation, associated with greater glutathione S-transferase activity, is a good health indicator in cows that consume phytoactive substances. The higher concentration of volatile fatty acids was due to the higher proportion of acetic acid in the ruminal fluid combined with lower butyric acid. Somatic cell counts in milk were lower in cows that consumed phytoactives during mid-lactation, as well as the effect of the treatment on Streptococcus spp. (lower in cows that consumed the additive). We conclude that consuming the additive benefits cows' health modulates rumen fermentation and nutrient digestibility, and positively affects milk production and quality.

Comparison of the Effects of Essential Oils from Cannabis sativa and Cannabis indica on Selected Bacteria, Rumen Fermentation, and Methane Production-In Vitro Study

This study aimed to evaluate the effects of essential oils (EOs) extracted from Cannabis sativa L. and Cannabis indica Lam. on in vitro ruminal fermentation characteristics, selected rumen microbial populations, and methane production. GC-MS analyses allowed us to identify 89 compounds in both EOs. It was found that E-β-caryophyllene predominated in C. sativa (18.4%) and C. indica (24.1%). An in vitro (Ankom) test was performed to analyse the control and monensin groups, as well as the 50 µL or 100 µL EOs. The samples for volatile fatty acids (VFAs), lactate, and microbiological analysis were taken before incubation and after 6 and 24 h. The application of EOs of C. indica resulted in an increase in the total VFAs of acetate and propionate after 6 h of incubation. The applied EOs had a greater impact on the reduction in methane production after 6 h, but no apparent effect was noted after 24 h. Lower concentrations of C. sativa and C. indica had a more pronounced effect on Lactobacillus spp. and Buryrivibrio spp. than monensin. The presented findings suggest that C. sativa and C. indica supplementation can modify ruminal fermentation, the concentrations of specific volatile fatty acids, and methane production.

Bridging the Gap: Harnessing Plant Bioactive Molecules to Target Gut Microbiome Dysfunctions in Amyotrophic Lateral Sclerosis

The correlation between neurodegenerative diseases and the gut microbiome is increasingly evident, with amyotrophic lateral sclerosis (ALS) being particularly notable for its severity and lack of therapeutic options. The gut microbiota, implicated in the pathogenesis and development of ALS, plays a crucial role in the disease. Bioactive plant molecules, specifically volatile compounds in essential oils, offer a promising therapeutic avenue due to their anti-inflammatory properties and gut-modulating effects. Our narrative review aimed to identify microbiota-associated bacteria in ALS and analyze the benefits of administering bioactive plant molecules as much-needed therapeutic options in the management of this disease. A comprehensive search of PubMed database articles published before December 2023, encompassing research on cell, human, and animal ALS models, was conducted. After selecting, analyzing, and discussing key articles, bacteria linked to ALS pathogenesis and physiopathology were identified. Notably, positively highlighted bacteria included Akkermansia muciniphila (Verrucomicrobia phylum), Faecalibacterium prausnitzii, and Butyrivibrio spp. (Firmicutes phylum). Conversely, members of the Escherichia coli spp. (Proteobacteria phylum) and Ruminococcus spp. (Firmicutes phylum) stood out negatively in respect to ALS development. These bacteria were associated with molecular changes linked to ALS pathogenesis and evolution. Bioactive plant molecules can be directly associated with improvements in the microbiome, due to their role in reducing inflammation and oxidative stress, emerging as one of the most promising natural agents for enriching present-day ALS treatments.

Fennel seeds dietary inclusion as a sustainable approach to reduce methane production and improve nutrient utilization and ruminal fermentation

Ruminants are considered a major producer of methane (CH4 ). Therefore, the present study aimed to determine the ability of dry fennel seeds to affect in vitro gas production and fermentation. Fennel seeds were included at 0% (Control), 0.5%, 1%, 1.5%, and 2% DM of a diet containing per kg DM: 500 g concentrate feed mixture, 400 g berseem hay, and 100 g of rice straw. The incubations lasted 48 h. Fennel seeds increased (P < 0.001) the asymptotic gas production and decreased its rate, while decreasing the production and proportion of CH4 (P < 0.05) and increased its rate. Moreover, fennel seed increased DM and neutral detergent fiber (P < 0.01) degradability, and increased total production of short-chain fatty acids, acetate, and propionate (P < 0.05). Compared to the control, fennel seeds increased (P < 0.01) metabolizable energy, partitioning factor, and microbial crude protein production. Overall, fennel seeds can be included up to 2% DM in ruminant diets as an environmentally friendly product in animal farming due to its ability to improve feed utilization, ruminal fermentation and while reducing CH4 production.

Silibinin reduces in vitro methane production by regulating the rumen microbiome and metabolites

This study used Silibinin as an additive to conduct fermentation experiments, wherein its effects on rumen gas production, fermentation, metabolites, and microbiome were analyzed in vitro. The silibinin inclusion level were 0 g/L (control group), 0.075 g/L, 0.15 g/L, 0.30 g/L, and 0.60 g/L (experimental group). Fermentation parameters, total gas production, carbon dioxide (CO2), methane (CH4), hydrogen (H2), and their percentages were determined. Further analysis of the rumen microbiome's relative abundance and α/β diversity was performed on the Illumina NovaSeq sequencing platform. Qualitative and quantitative metabolomics analyses were performed to analyze the differential metabolites and metabolic pathways based on non-targeted metabolomics. The result indicated that with an increasing dose of silibinin, there was a linear reduction in total gas production, CO2, CH4, H2 and their respective percentages, and the acetic acid to propionic acid ratio. Concurrent with a linear increase in pH, when silibinin was added at 0.15 g/L and above, the total volatile fatty acid concentration decreased, the acetic acid molar ratio decreased, the propionic acid molar ratio increased, and dry matter digestibility decreased. At the same time, the relative abundance of Prevotella, Isotricha, Ophryoscolex, unclassified_Rotifera, Methanosphaera, Orpinomyces, and Neocallimastix in the rumen decreased after adding 0.60 g/L of silibinin. Simultaneously, the relative abundance of Succiniclasticum, NK4A214_group, Candidatus_Saccharimonas, and unclassified_Lachnospiraceae increased, altering the rumen species composition, community, and structure. Furthermore, it upregulated the ruminal metabolites, such as 2-Phenylacetamide, Phlorizin, Dalspinin, N6-(1,2-Dicarboxyethyl)-AMP, 5,6,7,8-Tetrahydromethanopterin, Flavin mononucleotide adenine dinucleotide reduced form (FMNH), Pyridoxine 5'-phosphate, Silibinin, and Beta-D-Fructose 6-phosphate, affecting phenylalanine metabolism, flavonoid biosynthesis, and folate biosynthesis pathways. In summary, adding silibinin can alter the rumen fermentation parameters and mitigate enteric methane production by regulating rumen microbiota and metabolites, which is important for developing novel rumen methane inhibitors.

Essential Oils as a Dietary Additive for Small Ruminants: A Meta-Analysis on Performance, Rumen Parameters, Serum Metabolites, and Product Quality

There is an increasing pressure to identify natural feed additives that improve the productivity and health of livestock, without affecting the quality of derived products. The objective of this study was to evaluate the effects of dietary supplementation with essential oils (EOs) on productive performance, rumen parameters, serum metabolites, and quality of products (meat and milk) derived from small ruminants by means of a meta-analysis. Seventy-four peer-reviewed publications were included in the data set. Weighted mean differences (WMD) between the EOs treatments and the control treatment were used to assess the magnitude of effect. Dietary inclusion of EOs increased (p < 0.05) dry matter intake (WMD = 0.021 kg/d), dry matter digestibility (WMD = 14.11 g/kg of DM), daily weight gain (WMD = 0.008 kg/d), and feed conversion ratio (WMD = −0.111). The inclusion of EOs in small ruminants’ diets decreased (p < 0.05) ruminal ammonia nitrogen concentration (WMD = −0.310 mg/dL), total protozoa (WMD = −1.426 × 105/mL), methanogens (WMD = −0.60 × 107/mL), and enteric methane emissions (WMD = −3.93 L/d) and increased ruminal propionate concentration (WMD = 0.726 mol/100 mol, p < 0.001). The serum urea concentration was lower (WMD = −0.688 mg/dL; p = 0.009), but serum catalase (WMD = 0.204 ng/mL), superoxide dismutase (WMD = 0.037 ng/mL), and total antioxidant capacity (WMD = 0.749 U/mL) were higher (p < 0.05) in response to EOs supplementation. In meat, EOs supplementation decreased (p < 0.05) the cooking loss (WMD = −0.617 g/100 g), malondialdehyde content (WMD = −0.029 mg/kg of meat), yellowness (WMD = −0.316), and total viable bacterial count (WMD = −0.780 CFU/g of meat). There was higher (p < 0.05) milk production (WMD = 0.113 kg/d), feed efficiency (WMD = 0.039 kg/kg), protein (WMD = 0.059 g/100 g), and lactose content in the milk (WMD = 0.100 g/100 g), as well as lower somatic cell counts in milk (WMD = −0.910 × 103 cells/mL) in response to EOs supplementation. In conclusion, dietary supplementation with EOs improves productive performance as well as meat and milk quality of small ruminants. In addition, EOs improve antioxidant status in blood serum and rumen fermentation and decrease environmental impact.

Exploring the Addition of Herbal Residues on Fermentation Quality, Bacterial Communities, and Ruminal Greenhouse Gas Emissions of Paper Mulberry Silage

This study aimed to investigate the influence of herbal residues on the fermentation quality and ruminal fermentation of paper mulberry silage. Clove, mint, and purple perilla residues were used as additives. Silage treatments were designed as control (no additives), 5% of clove, 5% of mint, and 5% of purple perilla. After 21 and 75 days of fermentation, the fermentation characteristics, bacterial communities, and ruminal greenhouse gas emissions in vitro incubation of paper mulberry were analyzed. The results showed that the used herbal residues could reduce the protein losses in paper mulberry silage based on the lower contents of ammoniacal nitrogen and nonprotein nitrogen. Compared with control, higher lactic acid and propionic acid contents were observed in the silages treated with mint and purple perilla but with a higher acetic acid content in clove treatment. Real-time sequencing technology (single-molecule real-time) revealed that Lactobacillus was the dominant bacteria in all silages at the genus level, whereas the bacterial abundance in the treated silages differed greatly from control at the species level. Lactobacillus hammesii abundance was the highest in control, whereas Lactobacillus acetotolerans was the first predominant in the treated silages. All the additives enhanced the digestibility of in vitro dry matter significantly. However, purple perilla decreased the production of total gas, methane, and carbon dioxide. The findings discussed earlier suggested that herbal residues have potential effects in improving fermentation quality, reducing protein loss, and modulating greenhouse gas emissions in the rumen of paper mulberry silage by shifting bacterial community composition.

Dose-response effects of the Savory (Satureja khuzistanica) essential oil and extract on rumen fermentation characteristics, microbial protein synthesis and methane production in vitro

The objective of the present study was to investigate dose-response effects of the essential oil (EO) and dry extract (EX) of Satureja khuzistanica (SK) on in vitro gas production kinetics, rumen fermentation, ruminal methanogenesis and microbial protein synthesis. So, EO and EX were tested at 0 (as control); 150 (low dose); 300, 450 (intermediate doses) and 600 mg/L (high dose). The gas produced over 24 h of incubation (GP24) decreased linearly with both EO and EX dosages (P<0.01). In vitro methane production was reduced by both EO (14–69%, depending on the included dose) and EX (7–58%). Microbial protein (MP) as well as the efficiency of microbial protein synthesis (EMPS) were improved by EO (18.8–49.8% and 20.4–61.5% for MP and EMPS, respectively) and to a lesser extent by EX (8.3–25.7% and 4.6–24.2% for MP and EMPS, respectively). Ammonia concentration was dropped in linear and quadratic manners with EO (P<0.05), and linearly with EX dosages (P<0.01). EO and EX exhibited depressive effects (in linear and quadratic (P<0.05), and linear manners (P<0.01), respectively) on total protozoa count. A mixed linear and quadratic effect was observed from both EO and EX on total VFA concentration (P<0.01). Total VFA concentration increased at 300 mg/L of EX, but decreased at high dose of both EO and EX. The acetate proportion increased with EO intermediate and high dosages, but it decreased at the expense of propionate at low and intermediate doses of EX. In total, these findings confirmed previous research on the great capacity of plant-based feed additives in positively modulating rumen fermentation that their effects may vary depending on the used doses. Specifically, these results suggest that EO and EX have high potentials to improve rumen functions at intermediate doses, which needs to be confirmed by in vivo experiments.

Essential Oils in Livestock: From Health to Food Quality

Using plant essential oils (EOs) contributes to the growing number of natural plants' applications in livestock. Scientific data supporting the efficacy of EOs as anti-inflammatory, antibacterial and antioxidant molecules accumulates over time; however, the cumulative evidence is not always sufficient. EOs antioxidant properties have been investigated mainly from human perspectives. Still, so far, our review is the first to combine the beneficial supporting properties of EOs in a One Health approach and as an animal product quality enhancer, opening new possibilities for their utilization in the livestock and nutrition sectors. We aim to compile the currently available data on the main anti-inflammatory effects of EOs, whether encapsulated or not, with a focus on mammary gland inflammation. We will also review the EOs' antioxidant activities when given in the diet or as a food preservative to counteract oxidative stress. We emphasize EOs' in vitro and in vivo ruminal microbiota and mechanisms of action to promote animal health and performance. Given the concept of DOHaD (Developmental Origin of Health and Diseases), supplementing animals with EOs in early life opens new perspectives in the nutrition sector. However, effective evaluation of the significant safety components is required before extending their use to livestock and veterinary medicine.

Phytogenic Additives Can Modulate Rumen Microbiome to Mediate Fermentation Kinetics and Methanogenesis Through Exploiting Diet-Microbe Interaction

Ruminants inhabit the consortia of gut microbes that play a critical functional role in their maintenance and nourishment by enabling them to use cellulosic and non-cellulosic feed material. These gut microbes perform major physiological activities, including digestion and metabolism of dietary components, to derive energy to meet major protein (65-85%) and energy (ca 80%) requirements of the host. Owing to their contribution to digestive physiology, rumen microbes are considered one of the crucial factors affecting feed conversion efficiency in ruminants. Any change in the rumen microbiome has an imperative effect on animal physiology. Ruminal microbes are fundamentally anaerobic and produce various compounds during rumen fermentation, which are directly used by the host or other microbes. Methane (CH4) is produced by methanogens through utilizing metabolic hydrogen during rumen fermentation. Maximizing the flow of metabolic hydrogen in the rumen away from CH4 and toward volatile fatty acids (VFA) would increase the efficiency of ruminant production and decrease its environmental impact. Understanding of microbial diversity and rumen dynamics is not only crucial for the optimization of host efficiency but also required to mediate emission of greenhouse gases (GHGs) from ruminants. There are various strategies to modulate the rumen microbiome, mainly including dietary interventions and the use of different feed additives. Phytogenic feed additives, mainly plant secondary compounds, have been shown to modulate rumen microflora and change rumen fermentation dynamics leading to enhanced animal performance. Many in vitro and in vivo studies aimed to evaluate the use of plant secondary metabolites in ruminants have been conducted using different plants or their extract or essential oils. This review specifically aims to provide insights into dietary interactions of rumen microbes and their subsequent consequences on rumen fermentation. Moreover, a comprehensive overview of the modulation of rumen microbiome by using phytogenic compounds (essential oils, saponins, and tannins) for manipulating rumen dynamics to mediate CH4 emanation from livestock is presented. We have also discussed the pros and cons of each strategy along with future prospective of dietary modulation of rumen microbiome to improve the performance of ruminants while decreasing GHG emissions.

Top-dressing of chelated phytogenic feed additives in the diet of lactating Friesian cows to enhance feed utilization and lactational performance

The present experiment evaluated the inclusion of chelated phytogenic feed additives mixture in the diet of lactating cows for the first 3 months of lactation. A week before calving, thirty multiparous Friesian cows were divided into three treatments in a complete randomized design and fed a basal diet without supplementation (Control treatment), or the control diet supplemented with chelated phytogenic additives at 3 g (PHY3 treatment), or at 6 g/cow/d (PHY6 treatment). Menthol, levomenthol, β-linaloolm, anethole, hexadecanoic acid and pmenthane were the principal compounds identified in the additives mixture. Milk production, total solid, protein, fat, and lactose were increased with PHY3, but decreased by PHY6 (P<0.01). Whereas the PHY3 treatment increased (P<0.05) milk contents of Ca and Zn, PHY3 and PHY6 treatments increased (P<0.05) milk Fe and Mn concentrations. Though the PHY3 treatment increased (P<0.05) nutrient digestibility, the PHY6 treatment decreased (P<0.05) the digestibility of organic matter, crude protein and neutral detergent fiber. The PHY3 treatment increased (P<0.05) ruminal volatile fatty acids (VFA) concentration and proportional acetate and propionate and decreased butyrate, while the PHY6 treatment decreased ruminal VFA concentration and proportional acetate. The PHY3 treatment increased (P<0.05) serum total protein, glucose, total antioxidant capacity, and the concentrations of Ca and Zn. Both PHY3 and PHY6 treatment decreased (P<0.05) the concentrations of serum triglycerides, and cholesterol. Daily inclusion of 3 g/cow of chelated feed additives mixture in diet of lactating cows improved milk production and ruminal fermentation, but additives dose of 6 g/cow/d had negative impact on cows’ performance.

Effects of essential oils and(or) benzoic acid in beef finishing cattle diets on the fatty acid profile and shelf life stability of ribeye steaks and ground beef

The effects of feeding essential oils and(or) benzoic acid to finishing steers on fatty acid profile and oxidative stability (color and lipid oxidation) of beef longissimus thoracis steaks and ground beef was determined in this study. Beef was procured from crossbred beef steers (n = 63) fed one of five dietary treatments: (1) control (no antibiotics fed); (2) monensin/tylosin (monensin supplemented at 33 mg/kg [DM basis]; tylosin supplemented at 11 mg/kg [DM basis]); (3) essential oils (supplemented at 1.0 g/steer/day); (4) benzoic acid (supplemented at 0.5% [DM basis]); and (5) combination (essential oils supplemented at 1.0 g/steer/day and benzoic acid supplemented at 0.5% [DM basis]). Although no improvements in shelf life stability were observed, feeding finishing cattle essential oils and(or) benzoic acid did not have detrimental impacts on beef color stability and lipid oxidation over a simulated retail display period.

Phytogenic feed additives mixture enhances the lactational performance, feed utilization and ruminal fermentation of Friesian cows

The assay aimed to evaluate the effect of feeding a recently developed phytogenic feed additives mixture in diets of lactating Friesian cows (n = 30; 514 ± 10.1 kg body weight) for 3 months. Cows were stratified into three groups of 10 cows each and fed a control diet alone or the control diet supplemented with the additives mixture at 3 g (PHY3) or 6 g (PHY6)/cow daily. Menthol, levomenthol, β-linaloolm, anethole, hexadecanoic acid and p-menthane were the principle compounds identified in the additives mixture. The PHY3 increased (p < 0.01) intake and nutrient digestibility. PHY3 and PHY6 increased (p < 0.01) ruminal pH, total volatile fatty acids, propionate and acetate. PHY3 and PHY6 improved serum total protein and antioxidant capacity and decreased the concentrations of serum urea-N, triglycerides, total lipids, cholesterol and malondialdehyde (p < 0.05). PHY3 increased milk production and milk content of total solids, protein, lactose and fat. Both PHY3 and PHY6 did not affect mineral concentrations in blood or milk. It is concluded that the inclusion of 3 g/cow/d of feed additives mixture in the lactating Friesian cows diet enhanced milk production and feed utilization, with negative effects observed with increasing the dose of additives mixture to 6 g/cow daily.