Essential Oils as In Vitro Ruminal Fermentation Manipulators to Mitigate Methane Emission by Beef Cattle Grazing Tropical Grasses

Supplementation of a Basal Goat Diet With Incremental Doses of Canola Essential Oil Modulates In Vitro Rumen Fermentation and Microbial Diversity

BACKGROUND

Canola essential oil (CEO) contains linoleic and oleic fatty acids that can inhibit the growth of pathogenic micro-organisms and alter microbial digestion to increase ruminal fermentation and nutrient utilisation.

OBJECTIVES

The study evaluated the effect of supplementing a basal goat diet with incremental doses of CEO on chemical constituents and in vitro ruminal fermentation parameters and microbial diversity.

METHODS

Experimental treatments were a basal goat diet containing 0.0025% antibiotic growth promoter (AGP) without CEO (POSCON), a basal diet without AGP and CEO (NEGCON), and NEGCON supplemented with 0.5 (CEO5), 1.0 (CEO10), 1.5 (CEO15), and 2.0% (v/w) CEO (CEO20). The treatment samples were homogenised, oven-dried, milled and analysed for chemical constituents. For the in vitro experiment, each sample (1 g) was weighed into serum bottles containing a pre-mixed phosphate buffer solution (pH 6.8) and pre-warmed (39°C) overnight. Ruminal inoculum from three donor goats was used for the incubation. Rumen fermentation parameters and volatile fatty acids were determined and the 16s rRNA gene of the fermentation medium was sequenced and amplified to detect the archaea and bacteria abundance.

RESULTS

Dry matter and organic matter contents were lower (p < 0.05) for CEO15 and CEO20. Crude fat increased with CEO doses with the highest value recorded for CEO20. Treatment CEO20 produced the highest (p < 0.05) value for the immediately fermentable fraction, effective gas production and 96-h partition factor. Lag time had a positive quadratic effect whereas acetic and butyric acids conferred a positive quadratic effect in response to CEO inclusion. A total of 15 phyla, 46 genera and 65 species were identified. The Firmicutes, Bacteroidetes and Actinobacteria predominated the phyla groups while unclassified microbes, Prevotella and Succiniclasticum across all treatments predominated the genera and species. The genus Methanobrevibacter and Ruminococcus reduced significantly at CEO15 and CEO20.

CONCLUSION

The inclusion of CEO in a basal goat diet increased gas production, partition factor at 96 hour of incubation and decreased total volatile fatty acids. However, 1.5% CEO level enhanced the abundance of fermentative bacteria such as Firmicutes and Actinobacteria while 1.5% and 2% CEO levels reduced the abundance of methanogenic microbes.

Essential Oils in Nellore Beef Cattle: In Vivo Impact on Rumen Emissions

Essential oils (EOs), as rumen additives, decreased CH4 emissions in in vitro trials but results from in vivo studies are still limited. We investigated the effects of Origanum vulgare (OEO) and Thymus vulgaris (TEO) EOs on in vivo methane emissions from Nellore beef cattle. Six adult rumen-cannulated Nellore cattle were used in a double 3 × 3 Latin square design. Treatments consisted of three diets containing either 3 mL OEO per kg of concentrate, 3 mL TEO/kg of concentrate, or no EO addition. The experimental period consisted of three 21 d feeding periods and methane production was measured using the sulfur hexafluoride (SF6) technique from Day 16 to Day 21 of each feeding period. Intake, total apparent digestibility (dry matter as well as neutral and acid detergent fiber), and rumen parameters (pH, ammoniacal nitrogen concentration, and short-chain fatty acids) were also evaluated. The EOs did not decrease CH4 emissions and had no effect on rumen parameters.

Oregano Essential Oil in Livestock and Veterinary Medicine

With a growing global concern over food safety and animal welfare issues, the livestock and veterinary industries are undergoing unprecedented changes. These changes have not only brought challenges within each industry, but also brought unprecedented opportunities for development. In this context, the search for natural and safe products that can effectively replace traditional veterinary drugs has become an important research direction in the fields of animal husbandry and veterinary medicine. Oregano essential oil (OEO), as a natural extract, is gradually emerging in the fields of animal husbandry and veterinary medicine with its unique antibacterial, antioxidant, and multiple other biological activities. OEO not only has a wide antibacterial spectrum, effectively fighting against a variety of pathogenic microorganisms, but also, because of its natural properties, helps us to avoid traditional veterinary drugs that may bring drug residues or cause drug resistance problems. This indicates OEO has great application potential in animal disease treatment, animal growth promotion, and animal welfare improvement. At present, the application of OEO in the fields of animal husbandry and veterinary medicine has achieved preliminary results. Studies have shown that adding OEO to animal feed can significantly improve the growth performance and health status of animals and reduce the occurrence of disease. At the same time, pharmacokinetic studies in animals show that the absorption, distribution, metabolism, and excretion processes of OEO in animals shows good bioavailability. In summary, oregano essential oil (OEO), as a substitute for natural veterinary drugs with broad application prospects, is gradually becoming a research hotspot in the field of animal husbandry and veterinary medicine. In the future, we look forward to further tapping the potential of OEO through more research and practice and making greater contributions to the sustainable development of the livestock and veterinary industries.

AI-driven covalent drug design strategies targeting main protease (mpro) against SARS-CoV-2: structural insights and molecular mechanisms

The emergence of new SARS-CoV-2 variants has raised concerns about the effectiveness of COVID-19 vaccines. To address this challenge, small-molecule antivirals have been proposed as a crucial therapeutic option. Among potential targets for anti-COVID-19 therapy, the main protease (Mpro) of SARS-CoV-2 is important due to its essential role in the virus's life cycle and high conservation. The substrate-binding region of the core proteases of various coronaviruses, including SARS-CoV-2, SARS-CoV, and Middle East respiratory syndrome coronavirus (MERS-CoV), could be used for the generation of new protease inhibitors. Various drug discovery methods have employed a diverse range of strategies, targeting both monomeric and dimeric forms, including drug repurposing, integrating virtual screening with high-throughput screening (HTS), and structure-based drug design, each demonstrating varying levels of efficiency. Covalent inhibitors, such as Nirmatrelvir and MG-101, showcase robust and high-affinity binding to Mpro, exhibiting stable interactions confirmed by molecular docking studies. Development of effective antiviral drugs is imperative to address potential pandemic situations. This review explores recent advances in the search for Mpro inhibitors and the application of artificial intelligence (AI) in drug design. AI leverages vast datasets and advanced algorithms to streamline the design and identification of promising Mpro inhibitors. AI-driven drug discovery methods, including molecular docking, predictive modeling, and structure-based drug repurposing, are at the forefront of identifying potential candidates for effective antiviral therapy. In a time when COVID-19 potentially threat global health, the quest for potent antiviral solutions targeting Mpro could be critical for inhibiting the virus.

Potential effects of essential oils in safeguarding the health and enhancing production performance of livestock animals: The current scientific understanding

The food sector competes in a cutthroat environment, and it constantly struggles to maintain or even grow its market share. For customer confidence and consumption to remain strong, consistent animal products are needed. The qualitative attributes of the derived goods appear to be improved by the addition of bioactive substances to food, such as essential oils (EOs), and consumers are shielded from the impacts of bacterial and oxidative deterioration. Due to the current controversy surrounding synthetic chemicals and their alleged carcinogenic potential, a substantial study has been done to find effective and safe substitutes. Aromatic plants and the corresponding EOs from them are considered natural products and are typically employed in ruminant nutrition. Since dietary supplementation has been demonstrated to be an easy and practical method to successfully suppress oxidative processes or microbial deterioration at their localized sites, the addition of EOs in animal diets is now becoming a regular practice. However, there is just a little amount of evidence supporting the notion that these compounds may improve nutrient absorption and gastrointestinal health. Additionally, a variety of factors affect how well EOs works in animal diets. These variables can be, on the one hand, the erratic composition, and the many additions to the diet, and, on the other hand, erratic animal genetic elements. Maximizing the use of EOs and creating high-quality products require a deeper understanding of the composition and activity of the gastrointestinal tract microbiota. Numerous EOs contain bioactive substances with the potential to serve as multifunctional feed supplements for animals, with impacts on growth performance, the digestive system, the growth of pathogenic bacteria, and lipid oxidation, among others. To establish their regular use in animal production and to determine their precise mechanism of action, more research is required. The potential advantages of EOs for livestock health and production are highlighted in the current article.

Impact of Moringa oleifera on rumen fermentation and methane emission under in vitro condition

Exploring innovative methods to provide essential nutrients and reducing ruminant greenhouse gas emission is crucial for animal production and diminishing global warming. This study was conducted to examine the efficacy of Moringa oleifera leaves (ML) in ruminants at 0%, 5%, 10%, 15%, 20%, 30% and 40% level in different roughage (R) and concentrate (C) (80R:20C, 70R:30C and 60R:40C) under in vitro conditions. Chemical composition of ML, concentrate mixture and berseem were estimated. Rumen fermentation parameters of male goat kids viz., total gas production, CH4, true dry matter digestibility (TDMD), organic matter digestibility (TOMD), partial fraction (PF), microbial biomass (MBP), ammonia (N), acetate, propionate, butyrate and acetate propionate ratio were observed under in vitro conditions. Results revealed that crude protein, organic matter and ethyl ether content were higher in ML as compared to concentrate mixture and berseem. Magnesium and iron content were also higher in ML as compared to concentrate and berseem. Total gas production, digestibility of DM and OM, MBP, acetate and propionate level were improved (P < 0.05) upto 10–20% replacement. In contrast, decreased in CH4 (%) and CH4 (mL/100 mg dDM) was noted with increased levels of ML incorporation. There was no change observed in ammonia, acetate: propionate ratios at all the three planes of nutrition. In this study, it is concluded that mixing Moringa oleifera leaves in feed can be used as protein supplement and reduce the methane emission without causing any effect on digestibility and rumen fermentation parameters. However, ML can be suggested for widespread practice to attain the sustainable animal production (10–20%) and to alleviate the global warming.

Global Warming and Dairy Cattle: How to Control and Reduce Methane Emission

Agriculture produces greenhouse gases. Methane is a result of manure degradation and microbial fermentation in the rumen. Reduced CH4 emissions will slow climate change and reduce greenhouse gas concentrations. This review compiled studies to evaluate the best ways to decrease methane emissions. Longer rumination times reduce methane emissions and milk methane. Other studies have not found this. Increasing propionate and reducing acetate and butyrate in the rumen can reduce hydrogen equivalents that would otherwise be transferred to methanogenesis. Diet can reduce methane emissions. Grain lowers rumen pH, increases propionate production, and decreases CH4 yield. Methane generation per unit of energy-corrected milk yield reduces with a higher-energy diet. Bioactive bromoform discovered in the red seaweed Asparagopsis taxiformis reduces livestock intestinal methane output by inhibiting its production. Essential oils, tannins, saponins, and flavonoids are anti-methanogenic. While it is true that plant extracts can assist in reducing methane emissions, it is crucial to remember to source and produce plants in a sustainable manner. Minimal lipid supplementation can reduce methane output by 20%, increasing energy density and animal productivity. Selecting low- CH4 cows may lower GHG emissions. These findings can lead to additional research to completely understand the impacts of methanogenesis suppression on rumen fermentation and post-absorptive metabolism, which could improve animal productivity and efficiency.