Effect of feeding of blend of essential oils on methane production, growth, and nutrient utilization in growing buffaloes

Quantifying the Impact of Different Dietary Rumen Modulating Strategies on Enteric Methane Emission and Productivity in Ruminant Livestock: A Meta-Analysis

A meta-analysis was conducted with an aim to quantify the beneficial effects of nine different dietary rumen modulating strategies which includes: the use of plant-based bioactive compounds (saponin, tannins, oils, and ether extract), feed additives (nitrate, biochar, seaweed, and 3-nitroxy propanol), and diet manipulation (concentrate feeding) on rumen fermentation, enteric methane (CH4) production (g/day), CH4 yield (g/kg dry matter intake) and CH4 emission intensity (g/kg meat or milk), and production performance parameters (the average daily gain, milk yield and milk quality) of ruminant livestock. The dataset was constructed by compiling global data from 110 refereed publications on in vivo studies conducted in ruminants from 2005 to 2023 and anlayzed using a meta-analytical approach.. Of these dietary rumen manipulation strategies, saponin and biochar reduced CH4 production on average by 21%. Equally, CH4 yield was reduced by 15% on average in response to nitrate, oils, and 3-nitroxy propanol (3-NOP). In dairy ruminants, nitrate, oils, and 3-NOP reduced the intensity of CH4 emission (CH4 in g/kg milk) on average by 28.7%. Tannins and 3-NOP increased on average ruminal propionate and butyrate while reducing the acetate:propionate (A:P) ratio by 12%, 13.5% and 13%, respectively. Oils increased propionate by 2% while reducing butyrate and the A:P ratio by 2.9% and 3.8%, respectively. Use of 3-NOP increased the production of milk fat (g/kg DMI) by 15% whereas oils improved the yield of milk fat and protein (kg/d) by 16% and 20%, respectively. On the other hand, concentrate feeding improved dry matter intake and milk yield (g/kg DMI) by 23.4% and 19%, respectively. However, feed efficiency was not affected by any of the dietary rumen modulating strategies. Generally, the use of nitrate, saponin, oils, biochar and 3-NOP were effective as CH4 mitigating strategies, and specifically oils and 3-NOP provided a co-benefit of improving production parameters in ruminant livestock. Equally concentrate feeding improved production parameters in ruminant livestock without any significant effect on enteric methane emission. Therefore, it is advisable to refine further these strategies through life cycle assessment or modelling approaches to accurately capture their influence on farm-scale production, profitability and net greenhouse gas emissions. The adoption of the most viable, region-specific strategies should be based on factors such as the availability and cost of the strategy in the region, the specific goals to be achieved, and the cost-benefit ratio associated with implementing these strategies in ruminant livestock production systems.

The Effect of Monensin vs. Neem, and Moringa Extracts on Nutrient Digestibility, Growth Performance, Methane, and Blood Profile of Merino Lambs

Plant secondary compounds are potential rumen modifiers that can improve nutrient utilization in ruminant animals. This study evaluated the effect of Moringa (Moringa oleifera) and Neem (Azadirachta indica) leaf extracts on nutrient digestibility, growth performance, and enteric methane production in South African Mutton Merino lambs. Forty 4-month-old ram lambs with a mean body weight of 35 ± 2.2 kg were blocked by weight and from each block, lambs were randomly allocated into one of the following treatments: (i) diet only (fed a total mixed ration TMR-negative control), (ii) Monensin (fed TMR containing Monensin sodium, 15 mg/kg DM), (iii) Moringa (fed TMR, drenched with Moringa extract 50 mg/kg feed DM intake), and (iv) Neem (fed TMR, drenched with Neem extract 50 mg/kg DM intake). Extracts were administered via oral drenching at a concentration determined based on the previous week's feed intake. There were no differences in dry matter intake, average daily gain, feed conversion efficiency, digestibility, and nitrogen retention across the treatments. However, the extracts tended to reduce methane emitted both in g/head/day (p < 0.08) and g/ kg dry matter intake (p < 0.07). Extracts did not influence any of the blood metabolites in the ram lambs. Although the benefits of utilizing these medicinal plants as rumen modifiers under prolonged feeding conditions is justified, further evaluation is recommended to test Moringa and Neem leaf extracts at higher inclusion levels. Our research group is currently exploring a variety of phytogenic tools for the identification and standardization of key bioactive compounds linked to methane inhibition, in these leaf extracts.

Dietary Ruminant Enteric Methane Mitigation Strategies: Current Findings, Potential Risks and Applicability

This review examines the current state of knowledge regarding the effectiveness of different dietary ruminant enteric methane mitigation strategies and their modes of action together with the issues discussed regarding the potential harms/risks and applicability of such strategies. By investigating these strategies, we can enhance our understanding of the mechanisms by which they influence methane production and identify promising approaches for sustainable mitigation of methane emissions. Out of all nutritional strategies, the use of 3-nitrooxypropanol, red seaweed, tannins, saponins, essential oils, nitrates, and sulfates demonstrates the potential to reduce emissions and receives a lot of attention from the scientific community. The use of certain additives as pure compounds is challenging under certain conditions, such as pasture-based systems, so the potential use of forages with sufficient amounts of plant secondary metabolites is also explored. Additionally, improved forage quality (maturity and nutrient composition) might help to further reduce emissions. Red seaweed, although proven to be very effective in reducing emissions, raises some questions regarding the volatility of the main active compound, bromoform, and challenges regarding the cultivation of the seaweed. Other relatively new methods of mitigation, such as the use of cyanogenic glycosides, are also discussed in this article. Together with nitrates, cyanogenic glycosides pose serious risks to animal health, but research has proven their efficacy and safety when control measures are taken. Furthermore, the risks of nitrate use can be minimized by using probiotics. Some of the discussed strategies, namely monensin or halogenated hydrocarbons (as pure compounds), demonstrate efficacy but are unlikely to be implemented widely because of legal restrictions.

Effect of supplementing sulphate-reducing bacteria along with sulphur on growth performance, nutrient utilization and methane emission in goats

A competitive relationship exists between sulphate-reducing bacteria and methanogens in the anaerobic environment including rumen for hydrogen where sulphate is not limiting growth and consequently inhibit enteric methane emission as thermodynamically energetic sulphate reduction (∆G^o =  - 21.1 kJ/mole of H₂) is more favourable than methanogenesis (∆G^o =  - 16.9 kJ/mole H₂). To validate this hypothesis, a study was designed to investigate the effect of supplementation of sulphate-reducing bacteria (SRB) identified as Streptococcus caviae RM296 as microbial feed additives alone or along with sulphur (as sodium sulphate) on methane production, live weight gain, feed intake, nutrient digestibility and energy metabolism in goats. The experiment was conducted on growing kids (n = 36, 5-6 months of age) with average body weight of 10.08 ± 0.21 kg, divided into six groups (n = 6). The duration of the feeding trial was of 150 days. The six treatments were control fed a basal diet (T1), SRB 0.5 ml/kg BW (T2), sulphur (as sodium sulphate) 0.095% of DMI (total sulphur level in the diet 1.5 times the requirement) (T3), sulphur (as sodium sulphate) 0.095% of DMI + SRB 0.5 ml/kg BW (T4), sulphur (as sodium sulphate) 0.19% of DMI (total sulphur level in the diet 2 times the requirement) (T5) and sulphur (as sodium sulphate) 0.19% of DMI + SRB 0.5 ml/kg BW (T6). Duration of study was 150 days and goats were fed as per ICAR (2013) feeding standard. Methane (CH₄) production (l/kg DMI) was reduced by 11.8% (P = 0.052) in T6 where sulphur (0.19% DMI) was supplemented along with SRB4 (at the rate 0.5 ml/kg BW) as compared to T1 (un-supplemented group). However, the dry matter intake (DM), total weight gain (TG), average daily gain (ADG), feed conversion ratio (FCR), excretion of purine derivatives (allantoin, uric acid, xanthine and hypoxanthine) and digestibility of organic matter (OM), dry matter (DM), ether extract (EE), crude protein (CP), acid detergent fibre (ADF) and neutral detergent fibre (NDF) were similar (P > 0.05) among all the groups. The experimental data revealed that feeding of SRB as a microbial feed additive along with sulphur (as sodium sulphate) is capable of reducing enteric CH₄ emission without any adverse effect on rumen fermentation and digestibility of the nutrients.

Determinants of Ruminant Farmers' Use of Sustainable Production Practices for Climate Change Adaptation and Mitigation in Enugu State, Nigeria

A sustainable ruminant production system ensures economically viable livestock systems that meet the current and future demands of animal products as well as the environmental safety of current and future generations. The study analyzed the determinants of ruminant farmers' use of sustainable production practices for climate change adaptation and mitigation in Enugu State, Nigeria. Multistage sampling procedure was used to select ninety six (96) ruminant farmers that constituted the sample for the study. Semi-structured interview schedule with open ended questions was used in data collection. Data were analyzed using multiple regression and Pearson Moment Correlation statistics. Access to veterinary services (t = 2.056, p = 0.044), monthly household income (t = 3.582, p = 0.001) and annual income from ruminant production (t = −2.635, p = 0.011) were socio-economic factors that significantly influenced use of sustainable practices. The adjusted R- square implies that the three factors were able to explain 24% of variance in use of sustainable practices. There is a significant positive correlation (r = 0.426, p = 0.000) between knowledge level of farmers and their use of sustainable production practices. Schemes for financial inclusion such as payment for ecosystem services can spur farmers to adopt mitigation strategies. Improved climate change knowledge can enhance ruminant farmer's resilience to the increasing impacts of climate change.

Influence of dietary phytogenic feed additives on lactation performance, methane emissions and health status of Murrah buffaloes (Bubalus bubalis)

BACKGROUND

Several feed additives have been used in recent past to reduce enteric methane production in ruminants. But most of them also inhibit feed digestibility and rumen fermentation, thereby lowering animal performance. Phytogenic feed additives are gaining importance owing to their safety in regard to human health issues. The present study examined the effect of dietary supplementation of phytogenic feed additive containing a blend of poplar (Populus deltoides) and eucalyptus (Eucalyptus citriodora) leaves on feed utilization, milk production, methane emissions and health status of Murrah buffaloes (Bubalus bubalis).

RESULTS

The daily milk yield, 6% fat corrected milk yield, and fat-protein corrected milk yield were increased (P < 0.05) in phytogenic composite feed additive (PCFA)-supplemented buffaloes. A decrease (37.3%) in methane concentration in exhaled air of supplemented buffaloes was evident. The digestibility coefficient of dry matter, organic matter and neutral detergent fibre was increased (P < 0.05) in PCFA-fed buffaloes without affecting feed intake. Total digestible nutrient content of the ration fed to buffaloes of the PCFA group was significantly (P < 0.05) increased. The buffaloes fed PCFA exhibited an enhanced cell-mediated and humoral immune response.

CONCLUSION

A discernible positive impact was evident on overall performances and health status along with lowered methane production of buffaloes fed (15 g kg^-1 dry matter intake) a blend of phytogenic feed additive composed of leaves of poplar (P. deltoides) and eucalyptus (E. citriodora). © 2021 Society of Chemical Industry.

Research progress on the application of feed additives in ruminal methane emission reduction: a review

BACKGROUND

Ruminal methane (CH4) emissions from ruminants not only pollute the environment and exacerbate the greenhouse effect, but also cause animal energy losses and low production efficiency. Consequently, it is necessary to find ways of reducing methane emissions in ruminants. Studies have reported that feed additives such as nitrogen-containing compounds, probiotics, prebiotics, and plant extracts significantly reduce ruminant methane; however, systematic reviews of such studies are lacking. The present article summarizes research over the past five years on the effects of nitrogen-containing compounds, probiotics, probiotics, and plant extracts on methane emissions in ruminants. The paper could provide theoretical support and guide future research in animal production and global warming mitigation.

METHODS

This review uses the Web of Science database to search keywords related to ruminants and methane reduction in the past five years, and uses Sci-Hub, PubMed, etc. as auxiliary searchers. Read, filter, list, and summarize all the retrieved documents, and finally complete this article.

RESULTS

Most of the extracts can not only significantly reduce CH4 greenhouse gas emissions, but they will not cause negative effects on animal and human health either. Therefore, this article reviews the mechanisms of CH4 production in ruminants and the application and effects of N-containing compounds, probiotics, prebiotics, and plant extracts on CH4 emission reduction in ruminants based on published studies over the past 5 years.

CONCLUSION

Our review provides a theoretical basis for future research and the application of feed additives in ruminant CH4 emission reduction activities.

The impact of essential oils on antibiotic use in animal production regarding antimicrobial resistance - a review

Population growth directly affects the global food supply, demanding a higher production efficiency without farmland expansion - in view of limited land resources and biodiversity loss worldwide. In such scenario, intensive agriculture practices have been widely used. A commonly applied method to maximize yield in animal production is the use of subtherapeutic doses of antibiotics as growth promoters. Because of the strong antibiotic selection pressure generated, the intense use of antibiotic growth promoters (AGP) has been associated to the rise of antimicrobial resistance (AMR). Also, cross-resistance can occur, leading to the emergence of multidrug-resistant pathogens and limiting treatment options in both human and animal health. Thereon, alternatives have been studied to replace AGP in animal production. Among such alternatives, essential oils and essential oil components (EOC) stand out positively from others due to, besides antimicrobial effectiveness, improving zootechnical indexes and modulating genes involved in resistance mechanisms. This review summarizes recent studies in essential oils and EOC for zoonotic bacteria control, providing detailed information about the molecular-level effects of their use in regard to AMR, and identifying important gaps to be filled within the animal production area.

Abatement of enteric methane production from lactating Murrah buffaloes (Bubalus bubalis) with improving production performance and immune status through dietary supplementation of composite feed additive

Ruminant livestock production processes are the major sources of methane production in agriculture sector triggering global environmental pollution. Above 90% of world buffalo population present in Asian countries, India ranks first and contributes significantly to the environmental pollution by enteric methane emissions. In this study, we examined the effect of dietary composite feed additive supplementation on ruminal methane production, nutrient utilization, milk production and immune status of buffaloes (Bubalus bubalis). Eighteen lactating Murrah (Bubalus bubalis) buffaloes at early stage of lactation were divided into two groups of nine animals and fed a composite feed additive [consisted of (%, w/w) dried and ground leaves of Cordia dichotoma and Holoptelea integrifolia, 31.4 each; garlic oil, 0.6; sodium nitrate, 3.1; magnesium sulphate, 8.4; mustard oil, 12.6 and cottonseed oil, 12.5] which contained an ideal combinations of methane inhibitors, alternate hydrogen sinks and rumen stimulating agents to treatment (CFA) group animals along with basal feed of chaffed green sorghum (Sorghum bicolor) fodder, chaffed wheat straw and concentrate mixture for maintenance and milk production. The results showed a decrease (44.6%) in methane concentration in exhaled air of CFA group buffaloes with increase (p < 0.05) in digestibility of feed in comparison to control (CON). Total digestible nutrient (TDN) content of the ration fed to buffaloes of CFA group was significantly (p < 0.05) increased. The daily milk yield, 6% fat corrected milk (FCM) yield and immune response were also increased (p < 0.05) in CFA group. The study suggests that the supplementation of composite feed additive was effective to reduce enteric methane emissions and improvement in production performance and immune status of buffaloes.

The effects of dietary supplementation with 3-nitrooxypropanol on enteric methane emissions, rumen fermentation, and production performance in ruminants: a meta-analysis

The aim of this study was to investigate the effects of 3-nitrooxypropanol (NOP) on gas production, rumen fermentation, and animal performances depending on animal type using a meta-analysis approach. A database consisted of data from 14 studies, 18 experiments and 55 treatments. The supplementation of NOP linearly decreased methane (CH₄) emissions [g/kg dry matter intake (DMI)] regardless of animal type and length of experimental period (beef, p < 0.0001, R² = 0.797; dairy, p = 0.0003, R² = 0.916; and long term, p < 0.0001, R² = 0.910). The total volatile fatty acids (VFA) concentration and the proportion of acetate, based on beef cattle database, were significantly decreased with increasing NOP supplementation (p = 0.0015, R² = 0.804 and p = 0.0003, R² = 0.918), whereas other individual VFAs was increased. Based on the dairy database, increasing levels of NOP supplementation linearly decreased proportion of acetate (p = 0.0284, R² = 0.769) and increased that of valerate (p = 0.0340, R² = 0.522), regardless of significant change on other individual VFAs. In animal performances, the DMI, from beef cattle database, tended to decrease when the levels of NOP supplementation increased (p = 0.0574, R² = 0.170), whereas there was no significant change on DMI from dairy cattle database. The NOP supplementation tended to decrease milk yield (p = 0.0606, R² = 0.381) and increase milk fat and milk protein (p = 0.0861, R² = 0.321, p = 0.0838, R² = 0.322). NOP is a viable candidate as a feed additive because of its CH₄ mitigation effects, regardless of animal type and experiment period, without adverse effects on animal performances.

Potentials of patchouli (Pogostemon cablin) essential oil on ruminal methanogenesis, feed degradability, and enzyme activities in vitro

The effects of patchouli essential oil (PEO) as an alternative to antibiotics on ruminal methanogenesis, feed degradability, and enzyme activities were evaluated. The basal substrate was incubated without additives (control, CTL) and with monensin (MON, 6 μM/g DM) or patchouli essential oil (PEO, 90 μg/g DM) for 24 h. In three different runs, the gas production (GP) was recorded at 2, 4, 8, 12, and 24 h of incubation using a semi-automatic system. The results revealed that MON had decreased (P < 0.05) the net GP and CH₄ production and digestible and metabolizable energy relative to PEO supplementation. The in vitro truly degraded organic matter was not influenced by PEO application, while was reduced (P = 0.027) with MON. Both PEO and MON had similar reducing effect on the activity of carboxymethylcellulase (P = 0.030), in vitro truly degraded neutral detergent fiber (P = 0.010), NH₃-N concentrations (P = 0.012), acetate proportion (C2, P = 0.046), C2 to C3 ratio (P = 0.023), and total protozoal count (P = 0.017). Both additives recorded similar elevating potential on the α-amylase activity (P = 0.012), propionate (C3) proportion (P = 0.011), and microbial protein (P = 0.034) compared with CTL. Effects of MON and PEO on ruminal feed degradability, microbial enzyme activities, and total protozoa counts may be responsible for modifying rumen fermentation ecology. Addition of PEO may act as a desirable alternative rumen modifier for MON in ruminant diets.

Essential oils inhibit the bovine respiratory pathogens Mannheimia haemolytica, Pasteurella multocida and Histophilus somni and have limited effects on commensal bacteria and turbinate cells in vitro

AIMS

The objective of this study was to determine antimicrobial activities of essential oils (EOs) against bovine respiratory disease (BRD) pathogens and nasopharyngeal commensal bacteria, as well as cytotoxicity in bovine turbinate (BT) cells in vitro.

METHODS AND RESULTS

The chemical composition of 16 EOs was determined using gas chromatography-mass spectrometry. All EOs were first evaluated for growth inhibition of a single BRD pathogen Mannheimia haemolytica serotype 1 strain (L024A). The most inhibitory EOs (n = 6) were then tested for antimicrobial activity against multidrug-resistant strains of M. haemolytica (serotypes 1, 2 and 6); the BRD pathogens Pasteurella multocida and Histophilus somni, as well as commensal bacteria that were isolated from the nasopharynx of feedlot cattle. The cytotoxicity of 10 EOs was also evaluated using a BT cell line. The EOs ajowan, thyme and fennel most effectively inhibited all BRD pathogens tested including multidrug-resistant strains with minimum inhibitory concentrations (MIC) of ≤0·025% (volume/volume, v/v). For these EOs, the MIC was 2-32 fold greater against commensal bacteria, compared to BRD-associated pathogens. No cytotoxic effects of EOs against BT cells were observed within the tested range of concentrations (0·0125-0·4%, v/v).

CONCLUSIONS

The EOs ajowan, thyme and fennel inhibited M. haemolytica, P. multocida and H. somni at a concentration of 0·025% and had minimal antimicrobial activity against nasopharyngeal commensal bacteria and cytotoxicity against BT cells.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study demonstrated that EOs may have potential for intra-nasal administration to mitigate bovine respiratory pathogens in feedlot cattle.

Effect of Encapsulated Nitrate and Microencapsulated Blend of Essential Oils on Growth Performance and Methane Emissions from Beef Steers Fed Backgrounding Diets

A long-term study (112 days) was conducted to examine the effect of feeding encapsulated nitrate (NO₃-), microencapsulated blend of essential oils (EO), and their combination on growth performance, feeding behavior, and enteric methane (CH₄) emissions of beef cattle. A total of 88 crossbred steers were purchased and assigned to one of four treatments: (i) control, backgrounding high-forage diet supplemented with urea (1.17% in dietary DM); (ii) encapsulated NO₃- (EN), control diet supplemented with 2.5% encapsulated NO₃- as a replacement for urea (1.785% NO₃- in the dietary DM); (iii) microencapsulated blend of EO (MBEO), control diet supplemented with 150 mg/kg DM of microencapsulated blend of EO and pepper extract; and (iv) EN + MBEO, control diet supplemented with EN and MBEO. There was no interaction (p ≥ 0.080) between EN and MBEO on average dry matter intake (DMI), average daily gain (ADG), gain to feed ratio (G:F), feeding behavior, and CH₄ emission (using GreenFeed system), implying independent effects of feeding EN and MBEO. Feeding MBEO increased CH₄ production (165.0 versus 183.2 g/day; p = 0.005) and yield (18.9 versus 21.4 g/kg DMI; p = 0.0002) but had no effect (p ≥ 0.479) on average DMI, ADG, G:F, and feeding behavior. However, feeding EN had no effect on ADG and G:F (p ≥ 0.119) but reduced DMI (8.9 versus 8.4 kg/day; p = 0.003) and CH₄ yield (21.5 versus 18.7 g/kg DMI; p < 0.001). Feeding EN slowed (p = 0.001) the feeding rate (g of DM/min) and increased (p = 0.002) meal frequency (events/day). Our results demonstrate that supplementing diets with a blend of EO did not lower CH₄ emissions and there were no advantages of feeding MBEO with EN. Inclusion of EN as a replacement for urea reduced CH₄ emissions but had no positive impact on animal performance.