Decreased CH4 Production Research Articles

Evaluation of origanum oil, hydrolysable tannins and tea saponin in mitigating ruminant methane: In vitro and in vivo methods.

The objective of this study was to investigate the effects of origanum oil (ORO), hydrolysable tannins (HYT) and tea saponin (TES) on methane (CH4) emission, rumen fermentation, productive performance and gas exchange in sheep by using in vitro and in vivo methods. The ORO, HYT and TES additive levels were normalized per kg dry matter (DM) in both in vitro and in vivo experiments: ORO‐0, 10, 20 and 40 ml/kg; HYT‐0, 15, 30 and 60 g/kg; and TES‐0, 15, 30 and 60 g/kg, respectively. During in vitro incubation, 40 ml/kg ORO linearly decreased CH4 emission (p < 0.05); 20 and 40 ml/kg ORO cubically decreased carbon dioxide (CO2) production (p < 0.05), and rumen pH was cubically raised with the increasing ORO additive level (p < 0.01). The 60 g/kg HYT cubically decreased CH4 production (p < 0.05). The pH of 60 g/kg HYT was higher than that of 15 and 30 g/kg (p < 0.01); the pH of 20 g/kg TES was higher than that of 5 g/kg (p < 0.05). In the in vivo experiments, 40 ml/kg ORO inhibited dry matter intake (p < 0.01) cubically and reduced average daily gain (ADG) and feed conversion ratio (FCR) cubically (p < 0.05), and 20 or 40 ml/kg ORO linearly decreased CH4 production based on per day or metabolic weight (W0.75) (p < 0.05). Both 30 and 60 g/kg HYT linearly inhibited CH4 emission on the bases of per day and W0.75 (p < 0.05). The 20 g/kg TES improved the apparent digestibility of crude protein (p < 0.05), 10 and 20 g/kg of TES decreased CH4 emission (p < 0.05), and 5 g/kg of TES reduced O2 consumption and CO2 production (p < 0.05). In conclusion, these three plant extracts all showed the abilities on mitigating CH4 emission of sheep with appropriate additive ranges.

Improving ensiling characteristics by adding lactic acid bacteria modifies in vitro digestibility and methane production of forage-sorghum mixture silage

Improving the nutrition of livestock is an important aspect of global food production sustainability. This study verified whether lactic acid bacteria (LAB) inoculant could promote ensiling characteristics, nutritive value, and in vitro enteric methane (CH4) mitigation of forage sorghum (FS) mixture silage in attacking malnutrition in Zebu beef cattle. The FS at the soft dough stage, Cavalcade hay (CH), and cassava chip (CC) were obtained. The treatments were designed as a 4 × 2 factorial arrangement in a completely randomized design. Factor A was FS prepared without or with CH, CC, and CH + CC. Factor B was untreated or treated with Lactobacillus casei TH14. The results showed that all FS mixture silages preserved well with lower pH values below 4.0 and higher lactic acid contents above 56.4 g/kg dry matter (DM). Adding LAB boosted the lactic acid content of silages. After 24 h and 48 h of in vitro rumen incubation, the CC-treated silage increased in vitro DM digestibility (IVDMD) with increased total gas production and CH4 production. The LAB-treated silage increased IVDMD but decreased CH4 production. Thus, the addition of L. casei TH14 inoculant could improve lactic acid fermentation, in vitro digestibility, and CH4 mitigation in the FS mixture silages.

183 A blend of plant extracts (Actifor Pro) potentially reduced methane production in a dual-flow continuous culture system fed bermudagrass hay with or without corn gluten feed

Abstract Twelve dual-flow continuous culture fermenters (1.95 L) were used to evaluate the effect of a phytogenic feed additive (Actifor Pro, Delacon, Engerwitzdorf, Austria; ACT) on ruminal fermentation and methane production when fed high fiber diets, comprised of bermudagrass hay (BGH) with or without corn gluten feed (CGF). Fermenters were utilized in a generalized randomized block design with a 2 × 2 factorial arrangement of treatments (n = 6): 1) diet (with or without CGF at 22% of diet DM) and 2) additive (with or without ACT at 1.0 g/L ACT). Two 10-d periods were conducted. Overall, comparing to no CGF, supplementation with CGF resulted in lower dry matter, organic matter, crude protein digestibility, microbial efficiency of nitrogen utilization, and methane production (mL of CH4/mol of total VFA), but increased neutral detergent fiber digestibility (all P ≤ 0.05). Diet × additive interactions were observed for molar proportion of acetate and propionate, and acetate-to-propionate ratio (A:P, all interactions P &amp;lt; 0.05), where inclusion of ACT increased acetate molar proportion and A:P (both P &amp;lt; 0.05), and decreased propionate molar proportion in diets with CGF (P = 0.05). A diet × additive interaction was also observed for methane production (ml of CH4/mol of total VFA; P = 0.08), where ACT decreased CH4 production per mol of VFA by 42% (P = 0.04), when only BGH was fed to the fermenters. In conclusion, CGF supplementation in BGH diets reduced methane production and improved fiber digestibility. The decrease in methane production per mol of VFA observed with ACT in the BGH without CGF diet warrants further investigation.

44 Effect of Quebracho (Schinopsis balansae) extract inclusion in a high roughage diet upon in vitro gas production

Abstract The utilization of natural plant secondary compounds as feed additives in animal nutrition has been extensively studied because of their ability to modify digestive and metabolic functions. Condensed tannin (CT) supplementation can potentially alter ruminal fermentation, and mitigate methane (CH4) emissions. The objective of this study was to determine the effect of quebracho CT extract (QT; Schinopsis balansae) within a roughage-based diet on overall fermentability and CH4 production utilizing the in vitro gas production technique (IVGP). Twenty rumen cannulated steers (227 ± 19 kg) were randomly assigned to four dietary treatments (n=4): QT at 0, 1, 2, and 3% of DM (QT0, QT1, QT2, and QT3). A roughage-based diet containing 88% bermudagrass hay and 12% concentrate was fed daily at 2.1% of shrunk body weight. The animals were adapted to the basal diet for 24-d then introduced to predetermined treatments for 35d. Rumen inoculum was collected weekly from each steer to perform the incubations. Two hundred milligrams of air-dried base diet were incubated for 48-h with a composite rumen inoculum for each treatment over 5 wk. Kinetic analysis of cumulative 48h gas production was performed using Gasfit. Measurements of CH4 were performed via gas chromatography and digested residue was determined post-incubation. Data were analyzed using a random coefficients model. Total gas production was higher for QT0 compared to QT1 and QT3 (P = 0.001), but not different from QT2 (P = 0.554). The fractional rate of gas production was higher for QT2 compared to QT0 (P = 0.011). First and second pool gas production decreased linearly as QT inclusion increased (P = 0.042 and 0.010, respectively). There was no dietary effect in ivNDFD (P = 0.567). However, there was a linear tendency to decrease CH4 production with the addition of QT (P=0.071) likely due to changes in the microbial population.

Variable sediment methane production in response to different source-associated sewer sediment types and hydrological patterns: Role of the sediment microbiome

Production of methane (CH4), an essential anthropogenic greenhouse gas, from municipal sewer sediment is a problem deserving intensive attention. Based on long-term laboratory batch tests in conjunction with 16 s rRNA gene sequencing and metagenomics, this study provides the first detailed assessment of the variable sediment CH4 production in response to different pollution source-associated sewer sediment types and hydrological patterns, while addressing the role of the sediment microbiome. The high CH4-production capability of sanitary sewer sediment is shaped by enriched biologically active substrate and dominated by acetoclastic methanogenesis (genus Methanosaeta). Moreover, it involves syntrophic interactions among fermentation bacteria, hydrogen-producing acetogens and methanogens. Distinct source-associated microbial species, denitrifying bacteria and sulfate-reducing bacteria occur in storm sewer and illicit discharge-associated (IDA) storm sewer sediments. This reveals their insufficient microbial function capabilities to support efficient methanogenesis. Hydrogenotrophic methanogenesis (genus Methanobacterium) prevails in both these sediments. In this context, storm sewer sediment has an extremely low CH4-production capability, while IDA storm sewer sediment still shows significant carbon emission through a possibly unique mechanism. Hydrological connections promote the sewer sediment biodegradability and CH4-production capability. In contrast, hydrological disconnection facilitates the prevalence of acetoclastic methanogenesis, sulfate-reducing enzymes, denitrification enzymes and the sulfur-utilizing chemolithoautotrophic denitrifier, which drastically decreases CH4 production. Turbulent suspension of sediments results in relative stagnation of methanogenesis. This work bridges the knowledge gap and will help to stimulate and guide the resolution of ‘bottom-up’ system-scale carbon budgets and GHG sources, as well as the target CH4 abatement interventions.

Inhibitory effect of released phosphate on the ability of nano zero valent iron to boost anaerobic digestion of waste-activated sludge and the remediation method

The addition of nano zero valent iron (NZVI) to anaerobic systems is an attractive strategy to enhance the anaerobic digestion (AD) of waste-activated sludge (WAS). However, high minerals contents within the WAS may release inorganic salts and regenerate precipitates in AD, leading to changes in the morphology of the sludge and affecting mass transfer between syntrophic bacteria and methanogens. In this study, the addition of NZVI was found to significantly accelerate CH4 production early in the AD process of WAS. With continuous AD, the internal channels of the anaerobic granular sludge (AGS), which are crucial for mass transfer, were clogged by phosphate precipitates that were formed due to the reaction between Fe2+ and PO43− released from phosphorus-containing minerals in WAS. This caused a decrease in CH4 production. The combination of NZVI and granular activated carbon (GAC) reduced the production of phosphate precipitates due to the adsorption on Fe2+ by GAC; this mitigated the inhibitory effect of phosphate precipitates on CH4 production. Additionally, there was a sharp increase in genes involved in hydrogenotrophic methanogenesis in the NZVI and GAC + NZVI groups, while there was no significant change in the genes involved in acetoclastic methanogenesis in the NZVI group compared to the control group. The formation of H2 and the direct release of electrons from NZVI corrosion, which boost CH4 production, occurred simultaneously. This study is the first detailed investigation into the mechanisms underlying the inhibition and bioaugmentation effects of NZVI on AD of WAS in a complex system.

Inhibition of methanogenesis by nitrate, with or without defaunation, in continuous culture

Within the rumen, nitrate can serve as an alternative sink for aqueous hydrogen [H2(aq)] accumulating during fermentation, producing nitrite, which ideally is further reduced to ammonium but can accumulate under conditions not yet explained. Defaunation has also been associated with decreased methanogenesis in meta-analyses because protozoa contribute significantly to H2 production. In the present study, we applied a 2 × 2 factorial treatment arrangement in a 4 × 4 Latin square design to dual-flow continuous culture fermentors (n = 4). Treatments were control without nitrate (-NO3-) versus with nitrate (+NO3-; 1.5% of diet dry matter), factorialized with normal protozoa (faunated, FAUN) versus defaunation (DEF) by decreasing the temperature moderately and changing filters over the first 4 d of incubation. We detected no main effects of DEF or interaction of faunation status with +NO3-. The main effect of +NO3- increased H2(aq) by 11.0 µM (+117%) compared with -NO3-. The main effect of +NO3- also decreased daily CH4 production by 8.17 mmol CH4/d (31%) compared with -NO3-. Because there were no treatment effects on neutral detergent fiber digestibility, the main effect of +NO3- also decreased CH4 production by 1.43 mmol of CH4/g of neutral detergent fiber degraded compared with -NO3-. There were no effects of treatment on other nutrient digestibilities, N flow, or microbial N flow per gram of nutrient digested. The spike in H2(aq) after feeding NO3- provides evidence that methanogenesis is inhibited by substrate access rather than concentration, regardless of defaunation, or by direct inhibition of NO2-. Methanogens were not decreased by defaunation, suggesting a compensatory increase in non-protozoa-associated methanogens or an insignificant contribution of protozoa-associated methanogens. Despite adaptive reduction of NO3- to NH4+ and methane inhibition in continuous culture, practical considerations such as potential to depress dry matter intake and on-farm ration variability should be addressed before considering NO3- as an avenue for greater sustainability of greenhouse gas emissions in US dairy production.

3-Nitrooxypropanol decreases methane emissions and increases hydrogen emissions of early lactation dairy cows, with associated changes in nutrient digestibility and energy metabolism

The aim of this study was to determine the methane (CH4) mitigation potential of 3-nitrooxypropanol and the persistency of its effect when fed to dairy cows in early lactation. Sixteen Holstein-Friesian cows (all multiparous; 11 cows in their second parity and 5 cows in their third parity) were blocked in pairs, based on actual calving date, parity, and previous lactation milk yield, and randomly allocated to 1 of 2 dietary treatments: a diet including 51 mg of 3-nitrooxypropanol/kg of dry matter (3-NOP) and a diet including a placebo at the same concentration (CON). Cows were fed a 35% grass silage, 25% corn silage, and 40% concentrate (on dry matter basis) diet from 3 d after calving up to 115 d in milk (DIM). Every 4 weeks, the cows were housed in climate respiration chambers for 5 d to measure lactation performance, feed and nutrient intake, apparent total-tract digestibility of nutrients, energy and N metabolism, and gaseous exchange (4 chamber visits per cow in total, representing 27, 55, 83, and 111 DIM). Feeding 3-NOP did not affect dry matter intake (DMI), milk yield, milk component yield, or feed efficiency. These variables were affected by stage of lactation, following the expected pattern of advanced lactation. Feeding 3-NOP did not affect CH4 production (g/d) at 27 and 83 DIM, but decreased CH4 production at 55 and 111 DIM by an average of 18.5%. This response in CH4 production is most likely due to the differences observed in feed intake across the different stages of lactation because CH4 yield (g/kg of DMI) was lower (on average 16%) at each stage of lactation upon feeding 3-NOP. On average, feeding 3-NOP increased H2 production and intensity 12-fold; with the control diet, H2 yield did not differ between the different stages of lactation, whereas with the 3-NOP treatment H2 yield decreased from 0.429 g/kg of DMI at 27 DIM to 0.387 g/kg of DMI at 111 DIM. The apparent total-tract digestibility of dry matter, organic matter, neutral detergent fiber, and gross energy was greater for the 3-NOP treatment. In comparison to the control treatment, 3-NOP did not affect energy and N balance, except for a greater metabolizable energy intake to gross energy intake ratio (65.4 and 63.7%, respectively) and a greater body weight gain (average 0.90 and 0.01% body weight change, respectively). In conclusion, feeding 3-NOP is an effective strategy to decrease CH4 emissions (while increasing H2 emission) in early lactation Holstein-Friesian cows with positive effects on apparent total-tract digestibility of nutrients.

CFD-DEM study of biomass gasification in a fluidized bed reactor: Effects of key operating parameters

Abstract Biomass gasification in a fluidized bed reactor is a complex process involving intricately multi-scale and multi-physics processes and may be affected by many operating parameters. In this work, it is numerically investigated at particle scale using a coupled Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) approach. The flow dynamics, turbulence, heat transfer via convective, conductive, and radiative paths, and heterogeneous and homogeneous reactions are considered. The effects of key operating parameters on gasification performance are studied in terms of biomass particle diameter, initial bed temperature, steam to biomass (S/B) ratio, inlet gas flow rate, and feed position. The simulation results show biomass particle diameter has an insignificant influence on the production of H2 and CH4 while it slightly affects the production of CO and CO2. Higher initial bed temperature leads to a larger decrease of gas temperature at bed exit and benefits the production of H2 and CO. Increasing S/B ratio increases H2 and CO2 production while decreases CH4 and CO production. Larger inlet gas flow rate leads to a shorter gas residence time and the decrease of S/B ratio. Biomass particles fed from the side wall give rise to higher temperature, lower H2 and CO2, and higher CO and CH4 than that fed from the center bottom. Changing feed positions on the side wall has a slight influence on gas temperature while it has an insignificant influence on product compositions.

Ruminal Methanogenic Responses to the Thiamine Supplementation in High-Concentrate Diets.

Simple SummaryOptimal methane (CH4) mitigation strategy should decrease carbon footprint and meanwhile avoid causing hazard residues and productive reduction. Thiamine is a critical coenzyme in carbohydrates, and metabolism has been confirmed to effectively attenuate subacute ruminal acidosis (SARA). Whether thiamine supplementation impacts ruminal methanogenesis is still unclear. In the present study, thiamine supplementation in high-concentrate diets (HC) was conducted to investigate the impacts on ruminal methanogenesis process. Results indicated that thiamine supplementation in HC could efficiently reduce CH4 emissions compared with high-forage diets; meanwhile, it did not cause ruminal metabolic disorders compared with HC treatment. The effective decrease in methane production and changes of methanogens after thiamine supplementation in HC compared with high-forage diets contributed a better understanding of thiamine on ruminal carbohydrate metabolism. This finding here provided a brand-new perspective on mitigating methane emission in dairy cattle production, and an optimal strategy to decrease the carbon footprint without compromising the livestock production efficiency.Background: Thiamine supplementation in high-concentrate diets (HC) was confirmed to attenuate ruminal subacute acidosis through promoting carbohydrate metabolism, however, whether thiamine supplementation in HC impacts methane metabolism is still unclear. Therefore, in the present study, thiamine was supplemented in the high-concentrate diets to investigate its effects on ruminal methanogens and methanogenesis process. Methods: an in vitro fermentation experiment which included three treatments: control diet (CON, concentrate/forage = 4:6; DM basis), high-concentrate diet (HC, concentrate/forage = 6:4; DM basis) and high-concentrate diet supplemented with thiamine (HCT, concentrate/forage = 6:4, DM basis; thiamine supplementation content = 180 mg/kg DM) was conducted. Each treatment concluded with four repeats, with three bottles in each repeat. The in vitro fermentation was sustained for 48h each time and repeated three times. At the end of fermentation, fermentable parameters, ruminal bacteria and methanogens community were measured. Results: HC significantly decreased ruminal pH, thiamine and acetate content, while significantly increasing propionate content compared with CON (p < 0.05). Conversely, thiamine supplementation significantly increased ruminal pH, acetate while significantly decreasing propionate content compared with HC treatment (p < 0.05). No significant difference of ruminal methanogens abundances among three treatments was observed. Thiamine supplementation significantly decreased methane production compared with CON, while no significant change was found in HCT compared with HC. Conclusion: thiamine supplementation in the high-concentrate diet (HC) could efficiently reduce CH4 emissions compared with high-forage diets while without causing ruminal metabolic disorders compared with HC treatment. This study demonstrated that supplementation of proper thiamine in concentrate diets could be an effective nutritional strategy to decrease CH4 production in dairy cows.

Simulating the effects of soil temperature and soil moisture on CO2 and CH4 emissions in rice straw-enriched paddy soil

Paddy soil from a site in northeast China was incubated with 13C-labeled rice straw in a laboratory study, and the effects of soil temperature and moisture on CO2 and CH4 emissions were measured using stable isotope ratio mass spectrometry. Aerobic incubation experiments were conducted at three soil temperatures (−10 °C, 0 °C, and 10 °C) and two soil moistures (60% and 100% water-filled pore space (WFPS)) in a laboratory for 24 weeks to simulate the rice-fallow season. An anaerobic incubation experiment was carried out for 16 weeks under a soil temperature of 25 °C and a 1 cm submerged layer to simulate the rice-growing season. Our results showed that increases in both soil temperature and soil moisture significantly promoted the cumulative CO2 emissions from rice straw during aerobic incubation. Furthermore, during anaerobic incubation, the cumulative emissions of CO2 and CH4 from rice straw decreased with increasing aerobic incubation soil temperature and soil moisture. The CO2 and CH4 emission ratios from rice straw throughout the incubation duration ranged from 6.6–15.7% and 0.0–3.0%, respectively. The addition of rice straw promoted a priming effect on native soil organic carbon (SOC) mineralization and produced CO2 emissions, which positively impacted priming during the aerobic (rice-fallow season) and anaerobic incubation (rice-growing season). The positive priming effect of rice straw on the CO2 emission duration ranged from 75.0% to 274.3% by the end of the 40-week incubation period. Furthermore, the aforementioned effect first increased and then decreased as the aerobic incubation soil temperature increased, with the greatest effect at 0 °C and lowest at 10 °C. These results suggest that high temperature during the rice-fallow season promotes the decomposition of rice straw C and leads to a decreased positive priming effect on native SOC during the rice-fallow and rice-growing seasons under the seasonal conditions of northeast China, and that it also leads to decreased CH4 production during the rice-growing season. These results have scientific significance for rational utilization of rice straw and mitigation of greenhouse effect in northeast China.

Ecogenomics reveals community interactions in a long-term methanogenic bioreactor and a rapid switch to sulfate-reducing conditions.

The anaerobic digestion of wastes is globally important in the production of methane (CH4) as a biofuel. When sulfate is present, sulfate-reducing bacteria (SRB) are stimulated, competing with methanogens for common substrates, which decreases CH4 production and results in the formation of corrosive, odorous hydrogen sulfide gas (H2S). Here, we show that a population of SRB within a methanogenic bioreactor fed only butyrate for years immediately (within hours) responded to sulfate availability and shifted the microbial community dynamics within the bioreactor. By mapping shotgun metatranscriptomes to metagenome-assembled genomes, we shed light on the transcriptomic responses of key community members in response to increased sulfate provision. We link these short-term transcriptional responses to long-term niche partitioning using comparative metagenomic analyses. Our results suggest that sulfate provision supports a syntrophic butyrate oxidation community that disfavors poly-β-hydroxyalkanoate storage and that hydrogenotrophic SRB populations effectively exclude obligately hydrogenotrophic, but not aceticlastic, methanogens when sulfate is readily available. These findings elucidate key ecological dynamics between SRB, methanogens and syntrophic butyrate-oxidizing bacteria, which can be applied to a variety of engineered and natural systems.

Liquid hot water treatment of rice straw enhances anaerobic degradation and inhibits methane production during in vitro ruminal fermentation

Liquid hot water (LHW) treatment can be used to disrupt the fiber structure of rice straw. This in vitro ruminal batch culture study investigated the effect of LHW treatment on feed degradation, methane (CH4) production, and microbial populations. Rice straw was treated by LHW, and in vitro ruminal fermentation was performed using an automatic system with 72 h of incubation. Scanning electron microscopy showed that LHW treatment disrupted the physical structure of rice straw. Liquid hot water treatment decreased neutral detergent fiber and hemicellulose contents of the rice straw and increased neutral detergent solubles, water-soluble carbohydrates, and arabinose contents. Liquid hot water treatment increased dry matter degradation and volatile fatty acid concentration and decreased the acetate:propionate ratio, CH4 production, hydrogen accumulation, neutral detergent fiber degradation, and populations of protozoa, fungi, and cellulolytic bacteria. In summary, LHW treatment disrupted the cellulose-hemicellulose-lignin structure matrix of rice straw, leading to increased substrate degradability and decreased CH4 production. Therefore, the LHW treatment is a potential strategy to improve the nutritive value of forage such as rice straw and decrease the CH4 emissions in ruminants.

Moringa Oleifera Oil Modulates Rumen Microflora to Mediate In Vitro Fermentation Kinetics and Methanogenesis in Total Mix Rations.

This study was conducted to evaluate potential of Moringa oleifera seed oil (MOSO) to modulate rumen microflora to mitigate methane (CH4) production in different total mixed rations (TMRs). Three TMRs with different roughage (R) to concentrate (C) ratio were used as substrates (R70:C30, R50:C50 and R30:C70) for in vitro fermentation study using batch culture technique. Results revealed that supplementation of MOSO in different rations with variable roughage to concentrates ratio altered (P < 0.05) CH4 production and fermentation parameters. M. oleifera seed oil at 3 and 4% increased (P < 0.01) microbial protein (MCP) and propionate concentration for all rations but decreased acetate concentration in R70:C30 TMR. Two levels of MOSO (3 and 4%) quadratically increased (P = 0.001) MCP and decreased acetate in R30:C70 while all levels increased propionate. For R30:C70 and R50:C50 rations, MOSO linearly and quadratically decreased (P < 0.001) protozoa and methanogen counts; however, protozoa, methanogens and bacteria were significantly increased in R70:C30 ration without any change in fungal counts. Supplementation of higher level of MOSO (4%) in high roughage ration (R70:C30) showed negative effects on diversity (Shannon index) and evenness of bacterial species as compared to control and lower oil level. Moreover, it also decreased Firmicutes to Bacteroidetes ratio in high roughage rations more obviously at lower levels. Moringa oil also stimulated Prevotella in both high and low roughages diets that indicates its potential to mediate rumen acidosis. Conclusively, MOSO enhanced fermentation kinetics and decreased CH4 production through effective modulation of rumen microbiome.

PSXIV-13 Effect of phytochemicals on in vitro rumen fermentation and methane production

Abstract The objective of this study was to evaluate the effects of eight phytochemicals from four plant species, in two presentations, essential oils (EO) and aqueous extracts (AE) of garlic (GEO, GAE), cinnamon (CEO, CAE), eucalyptus (EEO, EAE) and rosemary (REO, RAE) on rumen fermentation, using the in vitro gas production technique. The experiment was set up as a completely randomized block design in a 2 × 4 factorial arrangement of treatments. All treatments were incubated with 0.5 g of a basal diet (BD; 50% concentrate, 20% alfalfa and 30% corn silage, dry matter basis). Additionally, BD and BD with 30 ppm of sodium monensin (MON) were used as controls. Phytochemicals were evaluated at a single dose of 900 mg/L of inoculum. In vitro dry matter digestibility (IVDMD), maximum volume of gas (Vmax), gas production rate (S) and lag phase (L) were evaluated. Methane (CH4) was determined indirectly, by fixation of CO2present in gas samples with 1M KOH solution, Non-fixed gas was assumed to be CH4. Methane production was correlated with organic matter fermented in the rumen (mL CH4/g OMFR). Data were analyzed using PROC MIXED of SAS ©. The effects of treatments were tested for the following contrasts: EO Vs AE, W Vs EO, W Vs AE. Some essential oils (GEO, CEO, REO) decreased CH4 production (mL CH4/g OMFR) and IVDMD by 20.4% and 17.8% compared to control treatments (BD and MON) (P &amp;lt; 0.05). Aqueous extracts showed a similar response (P &amp;lt; 0.05) to control treatments. In conclusion the use of essential oils negatively affected rumen fermentation and the production of CH4 in P cinnamon essential oil.

PSXII-20 Effects of association between monensin, calcium nitrate and tannin on enteric methane production in cannulated beef cattle

Abstract The objective of this experiment was to evaluate the association between different feed additives on ruminal fermentation parameters especially ruminal methane on cannulated beef cattle. Five Nellore cows, 480 ± 55 kg, ruminally cannulated were used. The experimental was a 5 x 5 Latin square design and the experimental unit was the animal within each period (n = 25 experimental units). The diets offered differed only by the inclusion or not of monensin, calcium nitrate or tannin, totaling five treatments: Control (without addition of additives), Monensin (30 ppm in the diet), Nitrate (3.0% of DM), Tannin (1.5% of DM) and Pool (combination of the three additives), being supplied in a basal diet with a concentrate: roughage (corn silage) ratio of 60:40. The study was divided into five periods, each one with 26 days. Sixteen days were used for adaptation to the experimental diets; ruminal fluid samples were collected at 0, 3, 6, 9 and 12h after feeding at 22nd day. To evaluate CH4 production and ammoniacal nitrogen balance, samples were incubated ex situ on equality ruminal conditions and then analyzed by gas chromatography and UV spectrophotometric, respectively. Data were analyzed using PROC MIXED of SAS and differences were declared significant at 5%. There was interaction between sampling time and treatment (P &amp;lt; 0001) and all the additives were efficient in decreasing the methane production in mol/g/hour (P &amp;lt; 0001), mol/kg/day (P &amp;lt; 0001) and g/kg/day (P &amp;lt; 0001). Comparing to the Control all additives decreased CH4 production, and decreases were 9.5% for monensin, 18.75% for tannin, 19.8% for calcium nitrate and 28.8% for the Pool (monensin, nitrate and tannin). Concentration and balance of rumen NH3-N was not affected by any treatments. It was possible to conclude that association of additives of different mechanism of action presented a partial additive effect.

PSXIV-21 Effect of high-tannin sorghum grain on rumen fermentation and methane production in vitro

Abstract Tannins are natural compounds with potential to reduce enteric methane (CH4) emissions in ruminants. High-tannin sorghum (HTS) varieties are cultivated in different regions of the world, including Mexico. The objective of this study was to evaluate the effects of HTS on rumen fermentation and CH4 production using a batch culture system. The experiment was set up as a completely randomized block design using a 3 × 5 factorial arrangement with 3 grains [HTS, low-tannin sorghum (LTS), and corn, with 19.6, 0.07 and 0 g of condensed tannins (CT)/kg dry matter (DM) respectively] and 5 grain to forage (alfalfa hay) proportions (20:80, 40:60, 60:40, 80:20 and 100:0). Data were analyzed using the MIXED procedure of SAS. Contrasts were used to determine linear and quadratic effects of grain:forage proportions. A decrease of 2.96% in CH4 concentration was observed for sorghum treatments compared to corn (P &amp;lt; 0.01). However, HTS and LTS were not different from each other (P = 0.76). Furthermore, CH4 production (mL/d) decreased (P &amp;lt; 0.01) by 19.13 and 8.53% with HTS compared with corn and LTS respectively. This reduction was associated with a decrease (P &amp;lt; 0.01) of 14.52 and 10.04% in total gas production with HTS as compared to corn and LTS. Both, CH4 and gas production decrease, were associated with reduced DM digestibility for HTS, which can be a negative effect of CT in HTS. Sorghum treatments produced 14.56% less CH4 (mL/g DM; P &amp;lt; 0.01) than corn. This was partially explained by a 7.98% decrease in DMD with sorghum treatments. As expected, gas production linearly increased and rumen pH linearly decreased with increasing levels of grain (P &amp;lt; 0.01). In conclusion, HTS had no advantage over LTS in terms of CH4 production. Nonetheless, sorghum grain, substituted for corn, can be an option to decrease CH4 production in ruminants, but digestibility might be compromised.

Effects of different barley and oat varieties on methane production, digestibility, and fermentation pattern in vitro

The objective of this in vitro study was to determine the effects of different barley and oat varieties on CH4 production, digestibility, and rumen fermentation patterns in dairy cows. Our hypothesis was that oat-based diets would decrease CH4 production compared with barley-based diets, and that CH4 production would differ between varieties within grain species. To evaluate this hypothesis, we conducted an in vitro experiment using a fully automated gas production technique, in which the total gas volume was automatically recorded by the system. The experiment consisted of triplicate 48-h incubations with 16 treatments, including 8 different varieties of each grain. The grain varieties were investigated as a mix with an early-cut grass silage (1:1 ratio of grain to silage on a dry matter basis) and mixed with buffered rumen fluid. We estimated predicted in vivo total gas production and CH4 production by applying a set of models to the gas production data obtained by the in vitro system. We also evaluated in vitro digestibility and fermentation characteristics. The variety of grain species did not affect total gas production, CH4 production, or fermentation patterns in vitro. However, in vitro-determined digestibility and pH were affected by variety of grain species. Grain species affected total gas and CH4 production: compared with barley-based diets, oat-based diets decreased total gas production and CH4 production by 8.2 and 8.9%, respectively, relative to dry matter intake. Grain species did not affect CH4 production relative to in vitro true dry matter digestibility. Oat-based diets decreased digestibility and total volatile fatty acid production, and maintained a higher pH at 48 h of incubation compared with barley-based diets. Grain species did not affect fermentation patterns, except for decreased molar proportions of valerate with oat-based diets. These results suggest that replacing barley with oats in dairy cow diets could decrease enteric CH4 production.

In vitro rumen fermentation of diets with different types of condensed tannins derived from sainfoin (Onobrychis viciifolia Scop.) pellets and hazelnut (Corylus avellana L.) pericarps

Information is lacking on the specific biological activity of feeds containing different types of condensed tannin (CT) on rumen fermentation characteristics. The aim of this study was to evaluate the in vitro rumen fermentation parameters of diets including sainfoin (Onobrychis viciifolia Scop.) pellets (PS) and/or hazelnut (Corylus avellana L.) pericarps (HP) using a batch culture system for 24 h. The treatments were a basal diet consisting of (dry matter (DM) basis) 800 g/kg hay from permanent grassland and 200 g/kg concentrate mix (control), the basal diet + 30.4% PS, the basal diet + 8.2% freeze-dried HP, and the basal diet + 15.2% PS + 4.1% HP. The diets were adjusted to be isotannic (20 g/kg DM, except for the control) and isoproteic (132 g/kg DM). Total gas and methane (CH4) productions were measured after 3.5 h and 24 h of incubation in buffered rumen fluid from sheep. At the end of incubation, pH, in vitro DM degradability (IVDMD) and the concentration of fermentation end-products in the medium were also measured. The CT structures in PS and HP, determined by the thiolysis method, were very different: PS had mostly prodelphinidins and HP mostly procyanidins. After 24 h of incubation, the total gas and CH4 productions and IVDMD were greater for the basal diet than for the CT-containing diets (P < 0.001). The CH4 production increased significantly with the diet + HP in the presence of polyethylene glycol (PEG, 4000 Da molecular weight), a CT-inactivating compound (P < 0.001), and tended to increase for the diet + PS (P = 0.062). The volatile fatty acid (VFA: acetate, propionate, butyrate, minor and iso-VFA) net productions were similar among treatments except for valerate (the lowest for PS-containing diets, P = 0.003), while the NH3 concentration was lower for the diet + PS (with a significant PEG effect) than for the diets including HP, and was highest for the basal diet. It was concluded that the inclusion of PS and HP in a basal diet for ruminants results in lower rumen fermentability and that their CT decreased CH4 production and protein degradability. The PS were more effective than HP for reducing rumen protein degradability with a potential increase of duodenal nitrogen (N) flow.

Effect of supplementation of various fermentable carbohydrate sources in sorghum straw-gliricidia mixed diet on fermentation kinetics measured using in vitro gas production

Supplementation of fermentable carbohydrate in crop by product-based diet is expected to improve the fermentability and reduced methane production. The study evaluated supplementation of various fermentable carbohydrate in sorghum straw-gliricidia mixture basal diet. Sorghum straw-gliricidia mixture was supplemented either with ground corn grain, rice bran or sorghum grain at 10% of DM basal diet. Treatment diets evaluated were: Sorghum + gliricidia leaf meal (Control); Control + 10% ground corn grain (Corn grain); Control + 10% rice bran (Rice bran); Control + 10% sorghum grain (Sorghum). Sorghum straw was chopped and ground then mixed with gliricidia leaf meal at ratio 60:40% DM. The sample was incubated for 48 hours, gas production was recorded at 4, 8,12, 16, 24, 36 and 48 hours. Rumen fluid for medium incubation was collected from sheep fed elephant grass basal diet. Supplementation of rice bran lowered (P<0.05) gas production from insoluble fraction of the diet compared to maize. Rice bran and sorghum decreased gas production at 48 h incubation compared to control (P<0.05). Sorghum supplementation decreased CH4 production. It can be concluded that fermentable carbohydrate supplementation from sorghum grain to sorghum straw-gliricidia mixture reduced percentage of methane production.