Reduce Methane Production Research Articles

Natural Ecuadorian zeolite: An effective ammonia adsorbent to enhance methane production from swine waste

Anaerobic digestion (AD) of swine waste allows obtaining renewable energy, biofertilizer and the reduction of environmental impacts. However, the low C:N ratio of pig manure generates high concentrations of ammonia nitrogen in the digestion process, reducing methane production. Zeolite is an effective ammonia adsorbent; thus, in this research the ammonia adsorption capacity of natural Ecuadorian zeolite was studied under different operating conditions. Subsequently, its effect on methane production from swine waste was evaluated using three doses of zeolite, 1.0, 4.0 and 8.0 g, in 1 L batch bioreactors. The results showed that the Ecuadorian natural zeolite has an adsorption capacity of around 19 mgNH3-N gZ−1 when using ammonium chloride solution and, an adsorption capacity between 37 and 65 mgNH3-N gZ−1 using swine waste. On the other hand, the addition of zeolite had a significant effect on methane production (p < 0.01). The zeolite doses that provided the highest methane production were 4.0 and 8.0 g L−1, which led to values of 0.375 and 0.365 Nm3CH4 kgVS−1, compared to the values of 0.350 and 0.343 Nm3CH4 kgVS−1 that were obtained for the treatments without addition of zeolite and using a dose of 1.0 g L−1, respectively. Addition of natural Ecuadorian zeolite meant not only a significant increase on methane production in the AD of swine waste, but also a better quality of the biogas with higher percentages of methane and lower concentrations of H2S.

Calcium Propionate Supplementation Mitigated Adverse Effects of Incubation Temperature Shift on In Vitro Fermentation by Modulating Microbial Composition

The ingestion of cold water in winter results in fluctuating decreases in rumen temperature, impacting rumen fermentation function and methane production. This study aimed to investigate the impact of calcium propionate (CaP) on rumen fermentation characteristics, methane production, and microbial microbiome under different in vitro incubation temperatures. A 2 × 2 factorial experiment was conducted over 72 h, with or without 2.5% CaP (dry matter [DM] basis) in substrate under a constant incubation temperature (39 °C, CIT) or shifting incubation temperatures (12 cycles in total, with each cycle consisting of 4 h of incubation at 39 °C followed by immediate transfer to 30 °C for 2 h, ITS). The results showed that ITS inhibited the gas production, methane production, and methane concentration at 12 and 72 h (p &lt; 0.05), and reduced the concentration of ammonium nitrogen (−14.25%), propionate (−16.14%), butyrate (−12.67%), and total volatile fatty acid (−8.50%) at 72 h more than the CIT groups (p &lt; 0.05). The addition of 2.5% CaP significantly increased the gas production at 72 h (+4.84%), asymptotic gas production (+5.08%, per 0.2 g DM substrate), concentration of propionate (+18.05%), and valerate (+9.45%) (p &lt; 0.05) compared to CaP-free groups, while it had no observable effect on the production or concentration of methane. Furthermore, the addition of 2.5% CaP yielded a significant increase in the relative abundance of Bacteroides (p &lt; 0.05). Under the ITS condition, the relative abundance of Methanomicrobiales decreased and was positively correlated with methane production at 72 h (r = 0.47, p &lt; 0.05). Additionally, CaP decreased the abundance of Prevotella_UCG_003 (p &lt; 0.05), which was negatively correlated with the asymptotic gas production (r = 0.45, p &lt; 0.05). Overall, our study suggests that the addition of 2.5% CaP can alleviate the adverse effects of ITS on in vitro fermentation parameters by regulating microbial composition and sustaining a reduction in methane production.

New Insight into Magnetic Enhanced Methane Production from Oily Sludge via Mesophilic Anaerobic Degradation Processes

Anaerobic digestion is a promising technology for treating and disposing of oily sludge, but the presence of oil in the sludge reduces methane production and sludge volume reduction. To overcome this limitation, this study creatively reports the use of magnetite to enhance methane production in oily sludge mesophilic anaerobic digestion and elucidates the underlying mechanism. Results show that the addition of magnetite increases methane production, with a 5% magnetite content leading to a 1.42-fold increase in cumulative methane output compared to the blank. Mechanistically, magnetite accelerates the release of organic matter, promotes oil degradation, increases volatile fatty acids (VFA) accumulation, and reduces the proportion of propionate. Additionally, magnetite alleviates pH decreases and increases the release of ammonia nitrogen and phosphate, resulting in effective sludge reduction, with volatile suspended solids (VSS) reduction ranging from 26.9% to 32.6%, higher than that of the blank. Moreover, magnetite accelerates electron transfer and increased the relative abundance of microorganisms associated with methane production, with the relative abundance of Methanosarcina increasing to 37.6~38.5% due to the presence of magnetite. This study provides a theoretical framework for effectively utilizing oily sludge through the application of magnetite.

Non-negligible roles of archaea in coastal carbon biogeochemical cycling.

Coastal zones are among the world's most productive ecosystems. They store vast amounts of organic carbon, as 'blue carbon' reservoirs, and impact global climate change. Archaeal communities are integral components of coastal microbiomes but their ecological roles are often overlooked. However, archaeal diversity, metabolism, evolution, and interactions, revealed by recent studies using rapidly developing cutting-edge technologies, place archaea as important players in coastal carbon biogeochemical cycling. We here summarize the latest advances in the understanding of archaeal carbon cycling processes in coastal ecosystems, specifically, archaeal involvement in CO2 fixation, organic biopolymer transformation, and methane metabolism. We also showcase the potential to use of archaeal communities to increase carbon sequestration and reduce methane production, with implications for mitigating climate change.

Effect of a garlic and citrus extract supplement on performance, rumen fermentation, methane production, and rumen microbiome of dairy cows

The aim of this trial was to determine the effect of a garlic and citrus extract supplement (GCE) on the performance, rumen fermentation, methane emissions, and rumen microbiome of dairy cows. Fourteen multiparous Nordic Red cows in mid-lactation from the research herd of Luke (Jokioinen, Finland) were allocated to 7 blocks in a complete randomized block design based on body weight, days in milk, dry matter intake (DMI), and milk yield. Animals within each block were randomly allocated to a diet with or without GCE. The experimental period for each block of cows (one for each of the control and GCE groups) consisted of 14 d of adaptation followed by 4 d of methane measurements inside the open circuit respiration chambers, with the first day being considered as acclimatization. Data were analyzed using the GLM procedure of SAS (SAS Institute Inc.). Methane production (g/d) and methane intensity (g/kg of energy-corrected milk) were lower by 10.3 and 11.7%, respectively, and methane yield (g/kg of DMI) tended to be lower by 9.7% in cows fed GCE compared with the control. Dry matter intake, milk production, and milk composition were similar between treatments. Rumen pH and total volatile fatty acid concentrations in rumen fluid were similar, whereas GCE tended to increase molar propionate concentration and decrease the molar ratio of acetate to propionate. Supplementation with GCE resulted in greater abundance of Succinivibrionaceae, which was associated with reduced methane. The relative abundance of the strict anaerobic Methanobrevibacter genus was reduced by GCE. The change in microbial community and rumen propionate proportion may explain the decrease in enteric methane emissions. In conclusion, feeding GCE to dairy cows for 18 d modified rumen fermentation and microbiota, leading to reduced methane production and intensity without compromising DMI or milk production in dairy cows. This could be an effective strategy for enteric methane mitigation of dairy cows.

Salt stress altered anaerobic microbial community and carbon metabolism characteristics: The trade-off between methanogenesis and chain elongation

Discharge of saline organic wastewater is increasing worldwide, yet how salt stress disrupts the microbial community's structure and metabolism in bioreactors has not been systematically investigated. The non-adapted anaerobic granular sludge was inoculated into wastewater with varying salt concentration (ranging from 0% to 5%) to examine the effects of salt stress on the structure and function of the anaerobic microbial community. Result indicated that salt stress had a significant impact on the metabolic function and community structure of the anaerobic granular sludge. Specifically, we observed a notable reduction in methane production in response to all salt stress treatments (r = −0.97, p < 0.01), while an unexpected increase in butyrate production (r = 0.91, p < 0.01) under moderate salt stress (1–3%) with ethanol and acetate as carbon sources. In addition, analysis of microbiome structures and networks demonstrated that as the degree of salt stress increased, the networks exhibited lower connectance and increased compartmentalization. The abundance of interaction partners (methanogenic archaea and syntrophic bacteria) decreased under salt stress. In contrast, the abundance of chain elongation bacteria, specifically Clostridium kluyveri, increased under moderate salt stress (1–3%). As a consequence, the microbial carbon metabolism patterns shifted from cooperative mode (methanogenesis) to independent mode (carbon chain elongation) under moderate salt stress. This study provides evidence that salt stress altered the anaerobic microbial community and carbon metabolism characteristics, and suggests potential guidance for steering the microbiota to promote resource conversion in saline organic wastewater treatment.

Physicochemical, thermal properties, and in vitro rumen fermentation of four different underutilized fruit by-products

Abstract. Fidriyanto R, Priadi G, Ridwan R, Nahrowi N, Jayanegara A. 2023. Physicochemical, thermal properties, and in vitro rumen fermentation of four different underutilized fruit by-products. Biodiversitas 24: 2416-2425. The objective of this study was to investigate the potential use of selected agricultural wastes consisting of Mangosteen (Garcinia mangostana L.) Peel (MGP), pomegranate (Punica granatum L.) Peel (PGP), kaffir lime (Citrus hystrix DC.) Peel (KLP), and Melastoma candidum D.Don Fruit (MCF) as ruminant feeds and enteric methane mitigation. The samples were analyzed for proximate, phytochemical, enzyme inhibition activity, XRD, FTIR, TGA, and in vitro rumen fermentation. The study found that MCF had the highest protein content (105.69 g/kg DM), while KLP had the lowest crude fiber (115.89 g/kg DM). MCF extract had the highest total phenol and flavonoid, and PGP extract had the highest enzyme inhibition activity. XRD analysis showed that KLP had the highest crystallinity (18.23%), followed by MCF (17.95%). KLP had the highest potential gas production (147.78 mL), followed by PGP (62.20 mL), MCF (27.86 mL), and MGP (4.46 mL). In addition, rumen digestibility, post-rumen digestibility, and VFA followed a similar pattern. The lowest methane production was observed in MGP and MCF. In conclusion, kaffir lime peel is potentially used as ruminant feed due to its higher digestibility and VFA production. Although MCF has lower digestibility, it is potentially used as a source of phenolic compounds to reduce methane production due to its higher phenolic and flavonoid content.

Seaweed Potential in Environmental Improving

Owing to the effect of frequent human activities, the climate nowadays on plaxnet earth has become more and more stressed. Pollutions such as greenhouse gases are products from factories and other human activities and have become extremely severe, for the damage they could cause to both human health and surrounding environments. For decades, scientists have been seeking ways to mitigate the situation (while minimizing the cost), and seaweeds, a cheap and widespread species can be a key solution to several problems. In this paper, we demonstrate 3 uses--seaweed as forage to reduce methane production by cattle, seaweed as a heavy metal filter, and seaweed-based biofuel--and the mechanism of each. By doing research on the existing literature, we find that seaweeds have considerable potential in alleviating environmental pressure.

Modulation of milking performance, methane emissions, and rumen microbiome on dairy cows by dietary supplementation of a blend of essential oils

Cattle represent a high contribution of the livestock's greenhouse gas emissions, mainly in the form of methane. Essential oils are a group of plant secondary metabolites obtained from volatile fractions of plants that have been shown to exert changes in the rumen fermentation and may alter feed efficiency and to reduce methane production. The objective of this study was to investigate the effect on rumen microbial population, CH4 emissions and milking performance of a mixture of essential oils (Agolin Ruminant, Switzerland) incorporated daily in the ration of dairy cattle. Forty Holstein cows (644 ± 63.5 kg of BW producing 41.2 ± 6.44 kg/d of milk with 190 ± 28.3 DIM) were divided into two treatments (n = 20) for 13 wk and housed in a single pen equipped with electronic feeding gates to control access to feed and monitor individual DM intake (DMI) on a daily basis. Treatments consisted of no supplementation (Control) or supplementation of 1 g/d of a blend of essential oils (BEOs) fed in the TMR. Individual milk production was recorded using electronic milk meters on a daily basis. Methane emissions were recorded using sniffers at the exit of the milking parlour. At day 64 of the study, a sample of rumen fluid was collected from 12 cows per treatment after the morning feeding using a stomach tube. There were no differences in DMI, milk yield, or milk composition between the two treatments. However, cows on BEO exhaled less CH4 (444 ± 12.5 l/d) than cows on Control (479 ± 12.5 l/d), and exhaled less (P < 0.05) CH4/kg of DM consumed (17.6 vs 20.1 ± 0.53 l/kg, respectively) from the first week of study, with no interaction with time, which suggests a fast action of BEO of CH4 emissions. Rumen relative abundance of Entodonium increased, and those of Fusobacteria, Chytridiomycota, Epidinium, and Mogibacterium decreased in BEO compared with Control cows. Supplementing 1 g/d of BEO reduces CH4 emissions on absolute terms (l/d) and diminishes the amount of CH4 produced by unit of DM consumed by cows relatively soon after the first supplementation, and the effect is sustained over time without impacting intake or milking performance.

Full-fat corn germ in diets for dairy cows as an alternative to ground corn.

The experiments reported in this research paper address the effects of replacing ground corn (GC) with full-fat corn germ (FFCG) on nutrient intake and digestibility, nitrogen utilization efficiency, performance, and predicted methane production in dairy cows fed cactus cladodes and sugarcane. We hypothesized that the inclusion of FFCG in the diet would not alter the performance of lactating cows but would reduce the predicted methane production in vivo. Ten multiparous Holstein cows at 90 ± 10 d of lactation and yielding 24.2 ± 3.5 kg milk/d were assigned to dietary treatments consisting of different levels of replacement of GC by FFCG (0; 25; 50; 75 and 100% of diet dry matter) in a replicated 5 × 5 Latin square design with 21-d periods. Methane production was predicted using an automated gas in vitro production system. Except for ether extract intake, which increased, the intake of all nutrients decreased linearly with the replacement of GC by FFCG. The digestibility of dry matter, organic matter and neutral detergent fiber reduced, whereas the digestibility of ether extract increased linearly with FFCG. There were no changes in the digestibility of crude protein. The nitrogen intake and daily excretion in urine and feces decreased, while nitrogen use efficiency increased linearly. There was no significant effect of diets on nitrogen balance or microbial protein synthesis and efficiency. The yield of protein, lactose and total solids in milk showed a quadratic behavior. On the other hand, milk fat yield and energy-corrected milk yield decreased linearly with the replacement of GC by FFCG. No effect on pH or ammonia nitrogen was observed. The production of methane (CH4, g/kg DM) and total CH4 (g/d), and CH4 intensity decreased linearly with the replacement of GC by FFCG. In conclusion, FFCG has been shown to be an effective source of fat to reduce methane production in dairy cows, partially supporting our initial hypothesis. However, as it decreases milk fat production, it is not recommended to replace more than 50% of GC by FFCG for lactating cows fed cactus cladodes and sugarcane.

Influence of &lt;i&gt;Artemisiae absinthil herba&lt;/i&gt; and &lt;i&gt;Inulae rhizomata et radices&lt;/i&gt; on fermentation processes and methanogenesis in the rumen of young cattle

Relevance. Herbal preparations and their biologically active compounds can improve the use of feed and increase the productivity of animals by changing the microbial fermentation of the rumen. In our work, we evaluated the effect of herbal preparations — rhizomes and roots of elecampane and wormwood herb, on metabolic processes in the rumen and methanogenesis.Methods. For the study: Inulae rhizomata et radices were used in dosages per 1 kg of CB: 3.0 g — 1st sample, 1.0 g — 2nd sample, 6.0 g — 3rd sample; Artemisiae absinthil herba in dosages per 1 kg of CB: 5.0 g — 4th sample, 2.0 g — 5th sample, 10.0 g — 6th sample. The study was carried out in vitro using the ANKOM Daisy II incubator (modifications D200 and D200I) according to a specialized technique. The scar content was obtained from Kazakh white-headed bulls with chronic scar fistula with an average weight of 220–225 kg at the age of 9–10 months. Air sampling to determine the level of methane was carried out on the device «Kristallux-2000M» by gas chromatography. The level of volatile fatty acids (VFA) in the contents of the scar was determined by gas chromatography on a gas chromatograph «Crystallux-4000M», determination of nitrogen forms — according to GOST 26180-84.Results. It was found that different dosages of herbal preparations did not significantly affect the characteristics of fermentation in the gastrointestinal tract. Wormwood grass at a dosage of 10.0 g per 1 kg of SV reduced methane production than its other dosages (p ≤ 0.05). Thus, a dose of 2.0 g showed an increase in the level of methane in rye by 36.5% (p ≤ 0.01), a dose of 5.0 g — by 47.5% (p ≤ 0.01). Rhizomes and roots of elecampane showed a high level of methane production, however, min and max administered doses of this phytobiotic showed a decrease of 38.1–38.6%.

Biodegraded hay with graded addition of Pleurotus ostreatus improves dry matter disappearance and reduces methane production of diets incubated in vitro

Bioconversion of plant material with white-rot fungi has demonstrated improvements in in vitro digestibility, however, effects on rumen fermentation parameters and methane (CH4) production, when included as a dietary ingredient, are not clear. The aim of this study was to assess changes in rumen fermentation parameters and in vitro CH4 production by dietary inclusion of ryegrass-fescue hay biodegraded with P. ostreatus (H-PO) during 14 days of solid fermentation. The experiment used 2 diets with contrasting acid detergent fibre (aADFom) content which were added with 0, 3 and 6% H-PO. Substrates were incubated 3 times with sampling at 24 h. Results were analysed by ANOVA, and compared with Tukey’s test and polynomial contrasts. Inclusion of H-PO at concentrations of 3 and 6% resulted in increased in vitro dry matter (DM) disappearance (IVDMD) by 10 and 12% respectively, whereas high concentrations of aADFom reduced IVDMD by 10% as compared to low aADFom. Methane production (mg/g DM incubated) and yield (mg/g DM degraded) were reduced by increasing aADFom and P. ostreatus biodegraded hay concentrations in the diets (p < 0.001) whereas concentrations of total short-chain fatty acids were not affected by the inclusion of biodegraded hay (p = 0.080) or aADFom concentration (p = 0.076). Increasing concentrations of biodegraded hay resulted in increased acetate (p < 0.001), and reduced propionate proportions (p = 0.021) but did not affect butyrate (p = 0.233). In conclusion the use of biodegraded hay as a pre-treated ingredient improved the utilisation of low and high fibre diets by increasing the in vitro disappearance, and decreasing CH4 emissions, without increasing the propionate proportion. HIGHLIGHTS The use of hay biodegraded with P. ostreatus (H-PO) improves the digestibility of ruminant diets. The use of H-PO decreases methane, and increases acetate production in in vitro conditions. The use of H-PO as an ingredient in ruminant diets could improve the sustainability of livestock systems.

Effect of Salt Content on Biogas Production and Microbial Activity: Review Study

Over the years, biogas production technology has advanced with the goal of reducing process costs and greenhouse gas emissions, and increasing biogas production. Several design factors and operational aspects must be taken into account in order to produce a stable and efficient biogas. When the substrates contain high salts, anaerobic treatment will be ineffective due to the disadvantages of high energy input and operating cost, membrane contamination, and low efficiency. This indicates that the treatment of high salinity organic waste is a big challenge. High salinity levels had a negative effect on bacterial growth through bacterial osmotic pressure metabolism. For example, high salinity can alter the course of fermentation and the accumulation of volatile fatty acids at high concentrations, as well as cause a decrease in methane yield and maximum rate of methane production, prolonging the late-stage period. A low level of salt concentration encourages the growth of bacteria since sodium is essential for the growth and metabolism of microorganisms in AD systems. When the sodium salt concentration is less than 8 g/L, there is no significant inhibition in the generation of methane. Addition of &gt;8 g/L NaCl, however, significantly reduced methane production (causing 17-80 percent inhibition). This paper focuses on understanding in detail how NaCl affects methane production and microbial activity, report salt concentrations that improve process efficiency and reduce inhibition, as well as review the modified kinetic model and demonstrate the effect of salt on methane production and delay in methanogenesis.

Strategies Used to Reduce Methane Emissions from Ruminants: Controversies and Issues

Methanogenesis plays a crucial role in the digestive process of ruminant animals. During this process, methanogenic archaea produce methane as a byproduct of their metabolism. However, the production of methane by ruminants is also a significant contributor to greenhouse gas emissions. Methane is a potent greenhouse gas that has a 28-fold greater global warming potential than carbon dioxide. Around 15% of all anthropogenic greenhouse gas emissions are generated by livestock. Therefore, reducing methane emissions from ruminant livestock is an important goal for reducing the environmental impact of agriculture. There is a variety of strategies that can be used to reduce methane emissions, including dietary modifications, genetic selection, microbiome manipulation, and feed additives, such as plant secondary metabolites, methane inhibitors, lipids, essential oils, and algae. The main and important objective of this paper is to critically discuss the current strategies proposed to reduce methane emissions from livestock. Though many strategies, such as chemical intervention, have remarkably reduced methane emissions from ruminants, their usage remains unappealing because of health and safety concerns as well as consumer decisions. Hence, genetic animal selection and biological feed additives, such as probiotics and secondary plant metabolites, have emerged as promising techniques for mitigating enteric methane emissions. These strategies are highly promising, but more intensive research is needed to validate these approaches and assess their effectiveness in reducing methane production by ruminants.

Micro- and Macro-Algae Combination as a Novel Alternative Ruminant Feed with Methane-Mitigation Potential

This study was conducted to provide alternative high-quality feed and to reduce methane production using a mixture of the minimum effective levels of Euglena gracilis, EG, and Asparagopsis taxiformis, AT. This study was performed as a 24 h in vitro batch culture. Chemical analysis demonstrated that EG is a highly nutritive material with 26.1% protein and 17.7% fat. The results showed that the supplementation of AT as a feed additive at 1 and 2.5% of the diet reduced methane production by 21 and 80%, respectively, while the inclusion of EG in the diet at 10 and 25% through partially replacing the concentrate mixture reduced methane production by 4 and 11%, respectively, with no adverse effects on fermentation parameters. The mixtures of AT 1% with both EG 10% and EG 25% had a greater reductive potential than the individual supplementation of these algae in decreasing methane yield by 29.9% and 40.0%, respectively, without adverse impacts on ruminal fermentation characteristics. These results revealed that the new feed formulation had a synergistic effect in reducing methane emissions. Thus, this approach could provide a new strategy for a sustainable animal production industry.

What Is a Drug? Enabling the Bioeconomy Through Updated Food and Drug Administration Policy

There are several emerging biotechnology and biomanufacturing innovations designed to improve the sustainability of the livestock and related commercial sectors. These include gene-edited animals, feed additives to reduce methane production, and cultivated meats. In the United States, disparate regulatory policies govern the commercialization of these products. Intentional genomic alterations (IGAs) in animals, and feed additives intended to reduce methane emissions, trigger federal regulatory oversight using the expensive and time-consuming new animal drug-approval pathway. Conversely, animal cells, with or without IGAs, cultured for human food production are evaluated using a “voluntary pre-market consultation” process. The current drug-centric regulatory policies for bioengineered animals and feed additives disincentivize investment, and the United States is starting to lag behind the rest of the world when it comes to the approval, and subsequent adoption of these innovations by farmers and ranchers at a time of increasing concern regarding the environmental footprint of animal agriculture.

Polycarbonate microplastics induce oxidative stress in anaerobic digestion of waste activated sludge by leaching bisphenol A.

Polycarbonate (PC) microplastics are frequently detected in waste activated sludge. However, understanding the potential impact of PC microplastics on biological sludge treatment remains challenging. By tracking the changes in methane production under different concentrations of PC microplastics, a dose-dependent effect of PC microplastics on anaerobic digestion of sludge was observed. PC microplastics at 10-60 particles/g total solids (TS) improved methane production by up to 24.7±0.1 % (at 30 particles/g TS), while 200 particles/g TS PC microplastics reduced methane production by 8.09±0.1 %. Bisphenol A (BPA) leached from 30 particles/g TS PC microplastics (1.26±0.18mg/L) down-regulated intracellular reactive oxygen species (ROS) production, thereby enhancing enzyme activity, biomass viability, and abundance of methanogenic (Methanobacterium sp. and Methanosarcina sp.), ultimately boosting methane production. Conversely, BPA leached from 200 particles/g TS PC microplastics (4.02±0.15mg/L) stimulated ROS production, resulting in decreased biomass viability and even apoptosis. Modulation of oxidative stress by leaching monomeric BPA is an underappreciated transformative mechanism for improving the mastery of the potential behavior of microplastics in biological sludge treatment.

Potential of nutritional strategies to reduce enteric methane emission in feedlot sheep: A meta-analysis and multivariate analysis

The objective of this study was to use meta-analytical methods to evaluate the effects of nutritional strategies on the reduction of enteric methane emission in feedlot sheep. Additionally, this study aimed to evaluate interrelationships among diet composition, intake and digestibility of nutrients, rumen parameters, rumen microbial population, nitrogen metabolism and enteric methane production in sheep. The dataset was composed by 45 peer-reviewed publications with 102 treatment means. The strategies to mitigate enteric methane emission were evaluated by examining the weighted mean difference between control treatment (diets containing no additives and/or any other strategies to mitigate methane emission) and reduced-methane treatment (diets containing strategies to mitigate methane emission: protozoa-free, nitrate, lipids, saponins, essential oils and tannins). The interaction of factors associated with diet composition, nutrient intake and digestibility, rumen parameters on methane emission from sheep depends on how methane production is expressed (Production=CH4 g/d vs Yield= CH4 g/kg DMI). Lipids inclusion to diets reduced methane production in 6.28 g/d and 5.87 g CH4/kg of DMI. Oil inclusion in amounts greater than 20 g oil/day reduced methane production (CH4 g/d). Lipid inclusion to diets presented the greatest effectiveness in reducing methane emission in sheep fed TMR diets containing different forage: concentrate ratios. Tannins inclusion to diets reduced methane production in 1.22 g/d CH4 and 2.61 gCH4/kg of DMI, presenting long-term effect on methane emission. Tannins effects on methane production were greater in sheep fed high-forage total mixed rations. Rumen defaunation (protozoa-free) and essential oils inclusion to diets had no effects on methane production. Although methane production reduced with saponin and nitrate inclusion to diets, further studies are needed to confirm their effects on methane emission and better elucidate factors interacting with the response of sheep to saponins and nitrate supplementation.

A low-carbon high inulin diet improves intestinal mucosal barrier function and immunity against infectious diseases in goats.

Abrupt weaning is a major stressful event, contributing to intestinal abnormalities and immune system dysfunction in weaned kids. Inulin is a prebiotic fiber with many positive functions, including promoting intestinal fermentation and enhancing host immunity in monogastric animals. However, the effects of a high-inulin, energy-rich diet on ruminal fermentation characteristics, methane emission, growth performance, and immune systems of weaned kids have not been investigated. A fully automated in vitro fermentation system was used to investigate ruminal fermentation characteristics and methane emission of a mixed substrate of inulin and fat powder (1.31: 1) in comparison with maize grain-based starter concentrate. During a 1-week adaptation and 4-week trial phase, 18 weaned kids (8.97 ± 0.19 kg) were randomly assigned to two groups, one with a conventional diet (83% maize grain; CON) and the other with a low-carbon, high-inulin diet (41.5% maize grain, 14.4% fat powder, 18.9% inulin; INU). In the in vitro rumen fermentation experiment, the total gas production was not different (p > 0.05); however, a lower (p < 0.05) methane production was observed for INU as compared to CON. The average daily gain and the ratio of feed intake and growth performance of kids fed with INU were higher (p < 0.05) than those fed with CON. Serum concentrations of alanine transaminase (ALT) and lactate dehydrogenase (LDH) were lower (p < 0.05), whereas the concentration of high-density lipoprotein (HDL) and cholesterol (CHOL) were higher (p < 0.05) in kids fed with the INU diet as compared CON. Dietary inulin significantly increased (p < 0.05) the secretion of immunoglobulins (IgA, IgG, and IgM) and inflammatory cytokines (IFN-γ and IL-10) in ileum tissue. Although no differences (p > 0.05) were observed in mRNA expression of tight junction markers, the INU diet tended to increase (p = 0.09) gene expression of ribosomal protein S6 kinase beta-1 (P70S6K) in the mammalian target of rapamycin (mTOR) pathway of longissimus dorsi muscle. Our findings highlighted that a low-carbon high-inulin energy-rich diet could be used as a promising strategy to improve gut immunity and growth performance of weaned kids under abrupt weaning stress and reduce methane production.

Influence of Cassia fistula leaf powder on in vitro ruminal fermentation, gas production and degradability of diets for ruminants

AbstractMedicinal plants with high phytochemical values are critical for enhancing the productivity of livestock systems, while reducing their environmental impact. This study investigated the influence of graded levels of Cassia fistula leaf powder (CFLP) on in vitro ruminal fermentation parameters, gas production and degradability of diets for ruminants. Five concentrate diets were formulated to contain varying levels of CFLP (0, 15, 30, 45 and 60 mg/g dry matter (DM), denoted CF0, CF15, CF30, CF45 and CF60, respectively). The concentrate diets combined with guinea grass hay at the ratio of 4 : 6 (concentrate : forage) served as a substrate for the study. In vitro gas production test was performed by incubating 200 mg DM of the substrate for 48 h. At the end of the incubation period, the total gas and methane production, nutrient digestibility, in vitro fermentation and post-incubation parameters were evaluated. Results revealed a linear decrease (P &lt; 0.001) in gas and methane production across the treatment groups with an increase in CFLP levels. The amount of methane produced varied from 9.3 ml/200 mg DM in the CF60 diet to 20 ml/200 mg DM in the control diet. Nutrient digestibility was highest in the control diet and lowest in the CF60 diet. There was a linear decrease in ammonia-nitrogen and total volatile fatty acid (TVFA) concentration with an increase in the CFLP level. Inclusion of CFLP up to 30 mg/g DM ruminant diet was found to reduce methane production and ammonia-nitrogen concentration with minimal effects on nutrient degradation and TVFA concentration.