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Inclusion of Asparagopsis armata in lactating dairy cows’ diet reduces enteric methane emission by over 50 percent
Abstract
Livestock production, particularly enteric methane production, contributes to greenhouse gas emissions globally. Various mitigation strategies developed to reduce enteric emissions have limited success. Although in vitro studies have shown a considerable reduction in methane emissions using Asparagopsis spp., no studies have been conducted to investigate the effect of any species of Asparagopsis in dairy cattle. Our objective was to evaluate quantitatively the response of cows consuming Asparagopsis armata on methane production (g/kg), yield (g/kg feed intake) and intensity (g/kg milk yield). Twelve post-peak lactating Holstein cows were randomly assigned to three treatments (control, 0.5% and 1% inclusion levels of A. armata on organic matter basis) in a 3 × 3 Latin square design with three 21-day periods. Enteric methane emissions were measured using the GreenFeed system. Methane production by cows decreased significantly by 26.4% at the low (0.5%) level of A. armata inclusion and 67.2% at the high (1%) level of inclusion. Feed intake was reduced by 10.8 and 38.0%, in cows fed the low and high level of macroalgae inclusion, respectively. Methane yield decreased significantly by 20.3 and 42.7% in cows fed diet including 0.5% and 1% A. armata inclusion levels, respectively (P = <0.0001). Methane intensity significantly decreased by 26.8% from cows fed at 0.5% level and 60% at the 1.0% A. armata inclusion level. Bromoform concentrations in milk were not significantly different between treatments. Our in vivo results showed that A. armata has potential to be used as a feed additive to reduce enteric methane emissions.
... Consequently, any non-conventional feed ingredient might elicit behavioural changes with consequences on intake, health and performance. Efforts geared towards sustainable food production, reduced environmental footprints of animal production and improved production efficiency necessitated the use of alternative non-conventional feed resources and feed additives, especially in ruminant diets [7][8][9][10]. Feed additives, such as 3-nitrooxypropanol (3-NOP), lipids and red seaweed (e.g., Asparagopsis taxiformis or Asparagopsis armata) are some of the common ones in ruminant diets gaining interest for their purported inhibitory effect on enteric methane emissions [7,8,[10][11][12]. ...
... Efforts geared towards sustainable food production, reduced environmental footprints of animal production and improved production efficiency necessitated the use of alternative non-conventional feed resources and feed additives, especially in ruminant diets [7][8][9][10]. Feed additives, such as 3-nitrooxypropanol (3-NOP), lipids and red seaweed (e.g., Asparagopsis taxiformis or Asparagopsis armata) are some of the common ones in ruminant diets gaining interest for their purported inhibitory effect on enteric methane emissions [7,8,[10][11][12]. Some of these additives (e.g., 3-NOP) are reported to reduce methane without significant decrease on DMI [12,13], whereas the inclusion of Asparagopsis spp. in ruminant diets consistently affected feed intake and performance [7,14] and, to some degree, gut health [8,14]. ...
... Feed additives, such as 3-nitrooxypropanol (3-NOP), lipids and red seaweed (e.g., Asparagopsis taxiformis or Asparagopsis armata) are some of the common ones in ruminant diets gaining interest for their purported inhibitory effect on enteric methane emissions [7,8,[10][11][12]. Some of these additives (e.g., 3-NOP) are reported to reduce methane without significant decrease on DMI [12,13], whereas the inclusion of Asparagopsis spp. in ruminant diets consistently affected feed intake and performance [7,14] and, to some degree, gut health [8,14]. For instance, at a 1% inclusion level (on an organic matter basis), Asparagopsis armata reduced DMI by about 38%, relative to the control diet in dairy cows [7], whereas Asparagopsis taxiformis (AT), at a 0.5% inclusion level, reduced DMI by about 18% in high and medium forage diets of beef steers [11]. ...
The current study assessed the effects of red macroalgae Asparagopsis taxiformis (AT)—included as an enteric methane inhibitor—in dairy cow diets on feed intake and eating–rumination behaviour. Fifteen early lactating Norwegian Red dairy cows were offered ad libitum access to drinking water and a total mixed ration (TMR) composed of 35% concentrate feed and 65% grass silage on a dry matter (DM) basis. The experiment lasted for 74 days with the first 22 days on a common diet used as the covariate period. At the end of the covariate period, the cows were randomly allocated into one of three dietary treatments: namely, 0% AT (control), 0.125% AT and 0.25% AT in the TMR. The TMR was offered in individual feed troughs with AT blended in a 400 g (w/w) water–molasses mixture. Eating–rumination behaviour was recorded for 11 days using RumiWatchSystem after feeding the experimental diets for 30 days. The 0.25% AT inclusion significantly reduced the DM intake (DMI). Time (min/d) spent on eating and eating in a head-down position increased with the increasing AT level in the diet, whereas rumination time was not affected. The greater time spent on eating head-down with the 0.25% AT group resulted in a significantly higher chewing index (min/kg DMI). Estimated saliva production per unit DMI (L/kg DMI, SE) increased from 10.9 (0.4) in the control to 11.3 (0.3) and 13.0 (0.3) in the 0.125% and 0.25% AT groups, respectively. This aligned with the measured ruminal fluid pH (6.09, 6.14, and 6.37 in the control, 0.125% AT and 0.25% AT groups, respectively). In conclusion, either the level of the water–molasses mixture used was not sufficient to mask the taste of AT, or the cows used it as a cue to sort out the AT. Studies with relatively larger numbers of animals and longer adaptation periods than what we used here, with varied modes of delivery of the seaweed may provide novel strategies for administering the additive in ruminant diets.
... The use of seaweed supplementation as an approach to reduce ruminal enteric CH 4 has been on-going for over a decade in vitro with a particular emphasis on Asparagopsis taxiformis, however their assessment in animal studies has only emerged in recent years. In general, the tropical, red seaweed Asparagopsis spp., has been shown to have antimethanogenic properties in studies conducted in vitro and with sheep (Li et al., 2016), beef (Roque et al., 2021), and dairy cattle (Roque et al., 2019). The antimethanogenic properties of A. taxiformis and other red seaweeds is thought to be mainly due to their relatively high content of the halogenated compound, bromoform, which can inhibit the cobamide-dependent methyl transferase step of the methanogenic pathway and hence block the production of CH 4 (Roque et al., 2019). ...
... In general, the tropical, red seaweed Asparagopsis spp., has been shown to have antimethanogenic properties in studies conducted in vitro and with sheep (Li et al., 2016), beef (Roque et al., 2021), and dairy cattle (Roque et al., 2019). The antimethanogenic properties of A. taxiformis and other red seaweeds is thought to be mainly due to their relatively high content of the halogenated compound, bromoform, which can inhibit the cobamide-dependent methyl transferase step of the methanogenic pathway and hence block the production of CH 4 (Roque et al., 2019). However, bromoform, a known carcinogen (Vaskoska, 2021), has been associated with ongoing health and environmental concerns (Abbott et al., 2020) even when included at low doses: addition of 67g DM A. taxiformis (84.42 µg bromoform) resulted in rumenitis and residues in both urine and milk (10 and 9.1 µg bromoform, respectively) after day 1 of feeding A. taxiformis (Muizelaar et al., 2021). ...
... The utility of seaweed as a ruminant feedstuff is impacted by the composition of the biomass which is affected by a multitude of inherent (species, growth rate, habitat) and external (temperature, light, nutrient availability) factors (Roque et al., 2019). The variation in CH 4 mitigation between both A. taxiformis samples is likely due to the amount of bromoform that has escaped from the biomass during storage prior to the experiment. ...
Inclusion of the red seaweed Asparagopsis taxiformis as a feed additive, has led to significant reductions in methane (CH4) production from ruminants. However, dietary supplementation with this seaweed is negatively associated with health and environmental concerns mainly due to its bromoform content, a compound with potential carcinogenic properties. Thus, there is renewed focus on ascertaining the anti-methanogenic potential of locally grown brown and green seaweeds, which typically do not contain bromoform. The objective of this study was to investigate the effects of selected brown and green seaweeds on diet digestibility, ruminal fermentation patterns, total gas (TGP) and CH4 production in vitro, using the rumen simulation technique system. In experiment 1, Pelvetia canaliculata (PEC) was examined. In experiment 2, Cystoseira tamariscifolia (CYT), Bifurcaria bifurcata (BIB), Fucus vesiculosus (FUV), Himanthalia elongata (HIM) and Ulva intestinalis (ULI) were analysed. Ascophyllum nodosum (ASC) was included in both experiments. A diet containing A. taxiformis (ASP1; ASP2) and an unsupplemented diet (CON) were included as positive and negative controls, respectively in both experiments. All seaweeds were included at a rate of 10 g/kg dry matter (DM) into a control diet of 50:50 (w:w) forage:concentrate. The seven brown and green seaweeds assessed failed to affect absolute CH4 emissions or alter fermentation patterns. In experiment 1, seaweed treatment had no effect on diet digestibility, CH4%, CH4 mmol/d or CH4 L/d (P>0.1), however ASP1 reduced CH4 mmol/g DOM by 49% (P<0.01) relative to the control. Both ASC and ASP1 tended to increase TGP (P<0.1) relative to the control. In addition to this, the inclusion of seaweed in experiment 1 reduced the production of NH3-N (P<.0001) compared to the control. In experiment 2, seaweed treatment had no effect on diet digestibility or TGP. Both ASP2 and FUV reduced CH4% (P<0.01) but only ASP2 significantly reduced CH4 mmol/d, CH4 L/d and CH4 mmol/g DOM (P<0.05). Daily mMol butyrate was reduced by ASP2 relative to the control and most other seaweeds (P<.0001). In both experiment 1 and 2, seaweed inclusion had no effect on daily total VFA, acetate or propionate production or the acetate:propionate ratio relative to the control. To conclude, including the bromoform-free brown and green seaweeds at 10g/kg DM has no negative effects on diet digestibility or fermentation patterns but also failed to reduce the production of enteric CH4 in vitro.
... Since then, there has been limited adoption in their use in nutrition of ruminant animals mainly due to the high costs involved with algal production and harvesting. Despite this, recent awareness around climate change has renewed interest in the use of macroalgae, e.g., the red seaweed As-paragopsis sp., as mitigators of enteric methane emissions from ruminants [6]. To be market viable, algae products require value adding through either carbon reduction funds or marketing linked to the sustainability of beef produced under low emission schemes. ...
... Both Asparagopsis taxiformis and Asparagopsis armata have shown to be effective in reducing methane but they contrast in efficacy most likely because of the concentration of bromoform in those species. For example, the concentration of bromoform in A. armata was 1.32 mg/g in the work of Roque et al. [6] compared to 6.55 mg/g in A. taxiformis in Kinley et al. [20]. Roque et al. [6] observed a reduction of 67.2% at an inclusion rate of 18.3 g/kg dry matter in lactating dairy cows whilst Kinley et al. [20] reported reductions of enteric CH4 production of up to 98% at a much lower inclusion, i.e., 3.26 g/kg dry matter, in beef cattle fed a high grain diet. ...
... For example, the concentration of bromoform in A. armata was 1.32 mg/g in the work of Roque et al. [6] compared to 6.55 mg/g in A. taxiformis in Kinley et al. [20]. Roque et al. [6] observed a reduction of 67.2% at an inclusion rate of 18.3 g/kg dry matter in lactating dairy cows whilst Kinley et al. [20] reported reductions of enteric CH4 production of up to 98% at a much lower inclusion, i.e., 3.26 g/kg dry matter, in beef cattle fed a high grain diet. Recently, Glasson et al. [72] discussed some of the benefits and risks involved in the feeding of Asparagopsis for the reduction of methane production from ruminants, including the effects it might have on atmospheric chemistry. ...
There is a wide range of algae species originating from a variety of freshwater and saltwater habitats. These organisms form nutritional organic products via photosynthesis from simple inorganic substances such as carbon dioxide. Ruminants can utilize the non-protein nitrogen (N) and the cell walls in algae, along with other constituents such as minerals and vitamins. Over recent decades, awareness around climate change has generated new interest into the potential of algae to suppress enteric methane emissions when consumed by ruminants and their potential to sequester atmospheric carbon dioxide. Despite the clear potential benefits, large-scale algae-livestock feedstuff value chains have not been established due to the high cost of production, processing and transport logistics, shelf-life and stability of bioactive compounds and inconsistent responses by animals under controlled experiments. It is unlikely that algal species will become viable ingredients in extensive grazing systems unless the cost of production and practical systems for the processing, transport and feeding are developed. The algae for use in ruminant nutrition may not necessarily require the same rigorous control during the production and processing as would for human consumption and they could be grown in remote areas or in marine environments, minimizing competition with cropping, whilst still generating high value biomass and capturing important amounts of atmospheric carbon. This review will focus on single-cell algal species and the opportunistic use of algal by-products and on-site production.
... Supplementing high doses of Asparagopsis can decrease DMI and milk production [49,89] and cause rumen mucosa abnormalities and inflammation [98,99]. Conversely, in other studies, supplementing Asparagopsis improved growth and feed efficiency [43,44]. ...
... Bro-moform, the main CH 4 -suppressing compound in Asparagopsis, is a suspected carcinogen and stratospheric-ozone-depleting agent [100], although the potential global ozone depletion caused by hypothetical global adoption of Asparagopsis was estimated to be relatively small [101]. Supplementing Asparagopsis has not resulted in the passage of bromoform to meat, milk, organs, or feces [43,44,49,89,98], with the exception of the first experimental day with non-adapted cows in the study by Muizelaar et al. [99]. However, supplementing Asparagopsis resulted in the passage of iodine and bromide to milk [89] and iodine to meat [44]. ...
... Maximizing the efficacy of inhibitors of rumen methanogenesis, i.e., 60% or more, will be important to substantially mitigate enteric CH 4 emissions. Meta-analyses and individual studies show that the extent of inhibition of methanogenesis by 3-NOP [29,30,32] and Asparagopsis is positively related to their dose [43,44,49,89,98] and to the content of bromoform in the case of Asparagopsis [100]. Therefore, if high-end doses are used, the extent of inhibition of rumen methanogenesis by feed additives is potentially greater than the averages obtained in meta-analyses. ...
This paper analyzes the mitigation of enteric methane (CH4) emissions from ruminants with the use of feed additives inhibiting rumen methanogenesis to limit the global temperature increase to 1.5 °C. A mathematical simulation conducted herein predicted that pronounced inhibition of rumen methanogenesis with pure chemicals or bromoform-containing algae with an efficacy higher than that obtained in most studies can be important to limiting global temperature increase by 2050 to 1.5 °C but will likely need to be accompanied by improved production efficiency and other mitigation measures. Currently, the most important limitations to the adoption of antimethanogenic feed additives are increased feeding cost without a consistent return in production efficiency and achieving sustained delivery of inhibitors to grazing animals, especially in extensive systems. Economic incentives could be applied in some countries to favor adoption of inhibitors. Changes in rumen microbial and whole animal metabolism caused by inhibiting methanogenesis could potentially be used to make the methanogenesis inhibition intervention cost-effective, although research in this direction is unlikely to yield results in the short term. Future research directions to maximize the adoption and efficacy of inhibitors of methanogenesis are examined.
... The bromoform concentration was reported to be highly variable within species. In red macroalgae, A. taximorfis and A. armata were reported to have 6.6-7.8 and 1.32 mg/g dry weight of bromoform, respectively (Kinley et al., 2020;Roque et al., 2019aRoque et al., , 2021. Brown macroalgae, however, were often reported to contain a far lower bromoform concentration. ...
... This shifting and re-directing use of H 2 could result in imbalance of CO 2 and H 2 to form CH 4 . Similar to many previous studies, macroalgae inclusion increased H 2 emissions in beef cattle (Roque et al., 2021) and dairy cows (Roque et al., 2019a; N = sample size; SE = standard errors; ADG = average daily gain; DMI = dry matter intake; FCM = fat corrected in milk; CH 4 = methane production; NH 3 -N = ammonia concentration; VFA = volatile fatty acid; C 2 = acetate; C 3 = propionate; C 4 = butyrate; C 5 = valerate; AIC = Akaike information criterion; RMSE = root mean-squared errors; R 2 = coefficient of determinant; L = linear model; L × Sp = P-value of interaction effect between seaweed levels × species of macroalgae. L × A = P-value of interaction effect between seaweed levels × type of animals. ...
... In several studies, however, the use of red macroalgae such as A. armata at 10 g/kg DM and A. taxiformis at 5 g/kg DM decreased DMI in dairy cows (Roque et al., 2019a;Stefenoni et al., 2021). Using similar supplementary level, A. taxiformis had no detrimental effect on ADG and DMI of beef cattle (Kinley et al., 2020;Roque et al., 2021) and sheep (Li et al., 2016). ...
A meta-analysis was performed to examine the dietary inclusion of marine macroalgae species to target methane (CH 4) reduction from ruminant animals and the effects on rumen fermentation and animal performance. A literature search was conducted from global scientific databases, resulting in 25 in vitro and 22 in vivo studies eligible to be integrated in a database. A total of 673 experimental units comprising 537 in vitro and 136 in vivo experimental units were analyzed by using mixed model methodology in SAS and multivariate analysis in R Studio. Principal component analysis (PCA) from in vitro dataset revealed difference effects of brown, green, and red macroalgae on CH 4 production without a pronounced pattern on rumen fermentation. Likewise, PCA from in vivo dataset supported the in vitro results whereas Ascophyllum nodosum (brown) and Asparagopsis taxiformis (A. taxiformis; red) species showed noticeably separated clusters on CH 4 production. Mixed regression analysis from in vitro and in vivo databases showed interaction effects (P<0.001) between levels × species on CH 4 production and the percentages of acetate (C 2), propionate (C 3), butyrate (C 4) whereas A. taxiformis showed the greatest effects on the decrease of C 2 and increase of C 3 proportions (P<0.001), among other species. Additionally, dietary levels of A. taxiformis had strong linear decrease (R 2 = 0.946; P<0.001) on CH 4 (g/d) and curvilinear effect on CH 4 when expressed as g/kg DMI (R 2 = 0.687; P<0.001). When considering the types of animals, A. taxiformis decreased (P<0.001) CH 4 by 64.76% in beef cattle but the effect in dairy cows and small ruminant were non-significant (P>0.05) compared with control diet as a reference. Curvilinear effect on in vitro organic matter digestibility (P=0.043) and linear degreased on crude protein digestibility (P=0.029) were found. Feeding macroalgae did not affect dry matter intake (DMI), average daily gain (ADG), milk production and milk composition except for milk lactose which linearly increased (R 2 = 0.731; J o u r n a l P r e-p r o o f 3 P=0.002) by increasing Ascophyllum nodosum level. In dairy cows, the inclusion of A. taxiformis increased iodine concentration by more than six-fold increase (P<0.001) while other species had no substantial effect on iodine concentration. Taken together, macroalgae can be used as feed ingredients for ruminants to decrease CH 4 emissions without detrimental effects on metabolism and production performance in ruminant livestock. Notwithstanding, feeding A. taxiformis > 10 g/kg DM of diet may result in an unfavorable effect on the high bromoform and iodine residuals in milk. Future in vivo study using less-explored species that had been tested in vitro need to be conducted.
... In vivo studies with sheep, steers, and dairy cows reported dose-and diet-dependent decreases between 9 and 98% of CH 4 production by supplementing Asparagopsis to the diet Roque et al., 2019aRoque et al., , 2021Kinley et al., 2020;Stefenoni et al., 2021). A substantial decrease in CH 4 yield for cattle was confirmed in a meta-analysis (Lean et al., 2021). ...
... A substantial decrease in CH 4 yield for cattle was confirmed in a meta-analysis (Lean et al., 2021). Efficacy of Asparagopsis for CH 4 mitigation depends on its concentration of bromoform, which ranges from 3.0 to 51.0 mg/kg of DMI (Kinley et al., 2020;Roque et al., 2019aRoque et al., , 2021Stefenoni et al., 2021). Additionally, Asparagopsis may be more effective at decreasing CH 4 production with high-concentrate than with highforage diets . ...
... Long-term oral exposure of animals to high concentrations of bromoform can cause liver and intestinal tumors; hence, the EPA (2000) classified the compound in Group B2: probable human carcinogen. Within the dietary concentrations used (<0.5% of seaweed/DMI), bromoform residues were not detected in milk, meat, fat, organs, or feces from sheep and beef or dairy cattle fed Asparagopsis Kinley, et al., 2020;Roque et al., 2019aRoque et al., , 2021. In contrast, Muizelaar et al. (2021), with no control animals in their study, reported passage of bromoform to milk in nonadapted dairy cows. ...
Ruminant livestock are an important source of anthropogenic methane (CH4). Decreasing the emissions of enteric CH4 from ruminant production is strategic to limit the global temperature increase to 1.5°C by 2050. Research in the area of enteric CH4 mitigation has grown exponentially in the last 2 decades, with various strategies for enteric CH4 abatement being investigated: production intensification, dietary manipulation (including supplementation and processing of concentrates and lipids, and management of forage and pastures), rumen manipulation (supplementation of ionophores, 3-nitrooxypropanol, macroalgae, alternative electron acceptors, and phytochemicals), and selection of low-CH4-producing animals. Other enteric CH4 mitigation strategies are at earlier stages of research but rapidly developing. Herein, we discuss and analyze the current status of available enteric CH4 mitigation strategies with an emphasis on opportunities and barriers to their implementation in confined and partial grazing production systems, and in extensive and fully grazing production systems. For each enteric CH4 mitigation strategy, we discuss its effectiveness to decrease total CH4 emissions and emissions on a per animal product basis, safety issues, impacts on the emissions of other greenhouse gases, as well as other economic, regulatory, and societal aspects that are key to implementation. Most research has been conducted with confined animals, and considerably more research is needed to develop, adapt, and evaluate antimethanogenic strategies for grazing systems. In general, few options are currently available for extensive production systems without feed supplementation. Continuous research and development are needed to develop enteric CH4 mitigation strategies that are locally applicable. Information is needed to calculate carbon footprints of interventions on a regional basis to evaluate the impact of mitigation strategies on net greenhouse gas emissions. Economically affordable enteric CH4 mitigation solutions are urgently needed. Successful implementation of safe and effective antimethanogenic strategies will also require delivery mechanisms and adequate technical support for producers, as well as consumer involvement and acceptance. The most appropriate metrics should be used in quantifying the overall climate outcomes associated with mitigation of enteric CH4 emissions. A holistic approach is required, and buy-in is needed at all levels of the supply chain.
... Halogenated compounds in Asparagopsis taxiformis appear to act as structural analogues of coenzyme M and thus inhibit the final step of the methanogenesis pathway . It has been shown that the decrease in abundance of methanogens in the rumen was positively correlated with the decrease of methanogenesis and increase in H2 emissions Roque et al., 2019a). Emissions of bromoform into the atmosphere may occur during the growth of seaweed or during desiccation processes (Keng et al., 2020), which would preventor at least greatly hamperthe farming of red seaweed on a commercial basis. ...
... Asparagopsis taxiformis, was identified as the most efficient(Machado et al., 2014). Low doses (2% OM incubated) of A. taxiformis almost eliminated in vitro CH4 production(Machado et al., 2016a), without any effect on forage digestibility and without compromising other fermentation parameters at a 5% OM supplementation rate(Roque et al., 2019a).The CH4-mitigating effect of red seaweed Asparagopsis spp. (A. ...
... taxiformis and A. armata) was recently confirmed in three in vivo trials.Li et al. (2016) reported a consistent (over a 72-day period) and dose-dependent reduction in CH4 emissions (−50% to −80%) when adding A. taxiformis at 1-3% of diet OM, respectively. In dairy cows, adding A. armata at 0.5% and 1% of diet OM reduced CH4 emissions (−26% and −67%, respectively) over 21 days while compromising animal performances (milk yield, intake) only at the high dose(Roque et al., 2019a). ...
... The total value of seaweed that is used for seaweed-based products was calculated as: v product = v mkt − (c transprod + c conv ) (22) where v product is the total value (cost, if negative) of seaweed used for products ($ tDW −1 ), v mkt is how much each ton of seaweed would sell for, given the current market price of conventional products that seaweed-based products replace ($ tDW −1 ), c transprod is as calculated in equation (21) and c conv is the cost to convert each ton of seaweed to a usable product ($ tDW −1 ). The annualized CO 2 emissions from transporting harvested seaweed and equipment back to port were calculated as: ...
... To calculate the total net cost and emissions from the production, harvesting, transport and conversion of seaweed for products, we combined the cost and emissions from the product-pathway cost and value modules. The total net cost of seaweed for products per ton DW was calculated as: (25) where c prodnet is the total net cost per ton DW of seaweed harvested for use in products, c prod is the net production cost per ton DW as calculated in equation (6) and v product is the net value (or cost, if negative) per ton DW as calculated in equation (22). The total net CO 2 -eq emissions avoided per ton DW of seaweed used in products were calculated as: e prodnet = e avprod − e prod (26) where e prodnet is the total net CO 2 -eq emissions avoided per ton DW of seaweed harvested annually (tCO 2 tDW −1 yr −1 ), e avprod is the net CO 2 -eq emissions avoided by seaweed products annually as calculated in equation (24) and e prod is the net CO 2 emitted from production and harvesting of seaweed annually as calculated in equation (9). ...
Net-zero greenhouse gas (GHG) emissions targets are driving interest in opportunities for biomass-based negative emissions and bioenergy, including from marine sources such as seaweed. Yet the biophysical and economic limits to farming seaweed at scales relevant to the global carbon budget have not been assessed in detail. We use coupled seaweed growth and technoeconomic models to estimate the costs of global seaweed production and related climate benefits, systematically testing the relative importance of model parameters. Under our most optimistic assumptions, sinking farmed seaweed to the deep sea to sequester a gigaton of CO2 per year costs as little as US$480 per tCO2 on average, while using farmed seaweed for products that avoid a gigaton of CO2-equivalent GHG emissions annually could return a profit of $50 per tCO2-eq. However, these costs depend on low farming costs, high seaweed yields, and assumptions that almost all carbon in seaweed is removed from the atmosphere (that is, competition between phytoplankton and seaweed is negligible) and that seaweed products can displace products with substantial embodied non-CO2 GHG emissions. Moreover, the gigaton-scale climate benefits we model would require farming very large areas (>90,000 km2)—a >30-fold increase in the area currently farmed. Our results therefore suggest that seaweed-based climate benefits may be feasible, but targeted research and demonstrations are needed to further reduce economic and biophysical uncertainties. Potential climate benefits of farming seaweed are large but sensitive to uncertain yields and competition with phytoplankton. Carbon removal by sinking seaweed is much costlier than avoiding emissions by substituting seaweed for land-based crops.
... There were no effects of plant extracts detected for gaseous emissions, while other experiments have shown dramatic reductions in CH 4 emissions with the incorporation of seaweed into the diet. This discrepancy may be due to the different seaweed species used in the experiments which detected effects on gaseous emissions in vivo and in vitro (Machado et al., 2014;Maia et al., 2016;Roque et al., 2019;Kinley et al., 2020). The seaweed used in the current experiment -Ecklonia radiata-is a brown seaweed, and to our knowledge, its effect on CH 4 emissions is unknown. ...
... Different species of seaweeds contain different bioactive compounds, for example red seaweeds (e.g., Asparagopsis) contain bromoform, which acts as a methane inhibitor. Further, the red seaweed (Asparagopsis) species used by Roque et al. (2019) and Kinley et al. (2020) was fed as a whole dry plant, rather than an extract. The current experiment had a relatively low number of animals with adequate visits (>20) to the AHCS with a larger than normal standard error of the mean, which may have contributed to the lack of treatment differences detected. ...
During the onset of lactation, dairy cows experience increases in metabolic demands causing an increase in metabolic and oxidative stress that may result in disorders and reduced milk production. Dairy cows also represent a source of negative environmental impacts. Accordingly, natural products which alleviate these stresses and sources of environmental pollutants would be beneficial. The objective of this experiment was to determine how commercial products Lactobacillus fermented seaweed (Ecklonia radiata) (SWO; Animal Health Tonic; AgriSea Ltd.; Paeroa, NZ) and Lactobacillus fermented seaweed plus terrestrial plants (SWP; Fortress+; Agrisea Ltd.; Paeroa, NZ) influence dairy cow oxidative stress, environmental impacts, and production. Pregnant multiparous Holstein-Friesian × Jersey cross dairy cows (n = 27; body weight = 488.8 ± 47.6, mean ± SD) received daily oral doses of water (CON), SWO, or SWP. During the prepartum period (i.e., last third of gestation) the cows received 5-mL of their respective treatments once daily and this dose was increased to 100-mL per cow per d following calving. Ruminal fluid and blood samples were collected on d 0, 38, and 80 and blood samples were again collected 3 days after calving. Total volatile fatty acids concentrations in ruminal fluid were 26% greater (P = 0.05) in animals administered SWP compared with CON during the prepartum period. The CON cows had greater (P < 0.05) whole blood glutathione peroxidase activity than cows on SWP and SWO at all-time points following treatment application. After 80-d of administering the treatments and 3-d post calving, SWO and SWP had greater (P < 0.05) total antioxidant status of plasma (marker of ability to reduce oxidants). Three days after calving, the SWO and SWP cows had less (P < 0.05) plasma non esterified fatty acid concentrations and urea nitrogen than CON cows. Further, the SWP treatment had the lowest concentration of milk urea N and was less (P < 0.05) than CON. Accordingly, the calculated daily urinary N excretion of SWP was 18.0% lower (P < 0.05) than CON and SWO had a tendency (P = 0.07) to have 14.7% lower urinary N excretion than CON. Collectively, these results highlight the ability for these Lactobacillus fermented plant products to reduce oxidative stress during the onset of lactation in dairy cows and to reduce environmental impacts. This experiment provides important information for the improvement in periparturient dairy cows’ health and environmental impacts, which have economically important implications.
... Furthermore, studies have demonstrated bromoform (halogenated compound) supplementation or supplementation with seaweed that contains this can reduce CH4 production (50% to 95%) and inhibit methanogenesis without negative effects on ruminal fermentation or animal growth performance [52]. However, if the ruminal medium is influenced, the risk of decreased DMI [53] affects ruminal degradability [54] and may alter ruminal microbiota [53], and growth and productivity can be affected. It is important to consider that some of these compounds are present in fresh form, but seaweed generally is treated to preserve it. ...
... Furthermore, studies have demonstrated bromoform (halogenated compound) supplementation or supplementation with seaweed that contains this can reduce CH4 production (50% to 95%) and inhibit methanogenesis without negative effects on ruminal fermentation or animal growth performance [52]. However, if the ruminal medium is influenced, the risk of decreased DMI [53] affects ruminal degradability [54] and may alter ruminal microbiota [53], and growth and productivity can be affected. It is important to consider that some of these compounds are present in fresh form, but seaweed generally is treated to preserve it. ...
Livestock production systems are responsible for producing ~18% of the total anthropogenic greenhouse gas (GHG) emissions. Numerous alternatives, such as feed additives or supplements, have been proposed to meet these challenges. Marine algae have been proposed for gas reduction in ruminants; nevertheless, there are still very few experimental reports. Thus, the objective of the current study was to identify the volatile organic compounds (VOCs) in three marine algae—Kelp (Macrocystis pyrifera), Ulva (Ulva spp.), and Silk (Mazzaella spp.)—and to test their in vitro ruminal fermentation characteristics, gas profiles, and ability to mitigate biogas production. The evaluation of the VOCs in marine algae was performed using a flash gas chromatography electronic nose (FGC-E-Nose). The in vitro study was elaborated through in vitro incubation and gas production. The data obtained were analyzed using a completely randomized design. In total, forty-three volatile compounds were identified for Kelp algae, thirty-eight were identified for Ulva algae, and thirty-six were identified for Silk algae; the compounds were from different chemical families and included aromas, alcohols, aldehydes, phenolics, carboxylic acids, esters, and nutraceutical properties. Dry matter degradability was significantly (p < 0.05) affected by the algae type. The cumulative ruminal gas production was different (p < 0.05) between treatments. Kelp algae presented a major (V; p < 0.05) volume of gas produced compared to the other algae. Lag time (l; p < 0.05) was increased by Kelp alga; however, there were no differences (p > 0.05) between the Silk and Ulva algae. The gas production rate was higher (s; p < 0.05) for Silk algae compared to the others. Ulva and Silk algae demonstrated a significant (p < 0.05) decrease in carbon dioxide emissions. Nevertheless, Kelp algae reduced the proportional methane (CH4) production (p < 0.05) after 48 h of incubation, with the lowest emission rate of 47.73%. In conclusion, algae have numerous bio compounds that provide some properties for use in ruminant diets as additives to reduce methane and carbon dioxide emissions.
... That report and other recent reviews (i.e., Beauchemin et al., 2020;Hegarty et al., 2021) outlined opportunities and limitations of practices aimed at mitigating enteric CH 4 . New developments in the field, such as research with the CH 4 inhibitor 3-nitrooxypropanol (3-NOP; Melgar et al., 2020aMelgar et al., ,b, 2021Schilde et al., 2021) and the macroalga Asparagopsis taxiformis (Li et al., 2018;Roque et al., 2019a;Kinley et al., 2020;Stefenoni et al., 2021) necessitate an updated analysis of available enteric CH 4 mitigation options. Therefore, the current review, which was part of the 2021 ADSA symposium titled "Production, Management and the Environment: Advances in Enteric Methane Mitigation in Dairy Cattle-The Last Decade and Future Prospects" (https: / / www .adsa ...
... (A. taxiformis and A. armata) appear to be the only ones with a confirmed mitigating effect in in vivo experiments with dairy and beef cattle (Li et al., 2018;Roque et al., 2019a;Kinley et al., 2020;Stefenoni et al., 2021). Our current understanding is that the antimethanogenic activity of Asparagopsis spp. is based on its content of lowmolecular-weight halogenated compounds, of which the brominated halomethane bromoform is dominant (Genovese et al., 2012). ...
Intensive research in the past decade has resulted in a better understanding of factors driving enteric methane (CH4) emissions in ruminants. Meta-analyses of large databases, developed through the GLOBAL NETWORK project, have identified successful strategies for mitigation of CH4 emissions. Methane inhibitors, alternative electron sinks, vegetable oils and oilseeds, and tanniferous forages are among the recommended strategies for mitigating CH4 emissions from dairy and beef cattle and small ruminants. These strategies were also effective in decreasing CH4 emissions yield and intensity. However, a higher inclusion rate of oils may negatively affect feed intake, rumen function, and animal performance, specifically milk components in dairy cows. In the case of nitrates (electron sinks), concerns with animal health may be impeding their adoption in practice, and potential emission trade-offs have to be considered. Tannins and tanniferous forages may have a negative effect on nutrient digestibility, and more research is needed to confirm their effects on overall animal performance in long-term experiments with high-producing animals. A meta-analysis of studies with dairy cows fed the CH4 inhibitor 3-nitrooxypropanol (3-NOP) at the Pennsylvania State University showed (1) a consistent 28 to 32% decrease in daily CH4 emissions or emissions yield and intensity; (2) no effect on dry matter intake, milk production, body weight, or body weight change, and a slight increase in milk fat concentration and yield (0.19 percentage units and 90 g/d, respectively); 3-NOP also appears to increase milk urea nitrogen concentration; (3) an exponential decrease in the mitigation effect of the inhibitor with increasing its dose (from 40 to 200 mg/kg of feed dry matter, corresponding to 3-NOP intake of 1 to 4.8 g/cow per day); and (4) a potential decrease in the efficacy of 3-NOP over time, which needs to be further investigated in long-term, full-lactation or multiple-lactation studies. The red macroalga Asparagopsis taxiformis has a strong CH4 mitigation effect, but studies are needed to determine its feasibility, long-term efficacy, and effects on animal production and health. We concluded that widespread adoption of mitigation strategies with proven effectiveness by the livestock industries will depend on cost, government policies and incentives, and willingness of consumers to pay a higher price for animal products with decreased carbon footprint.
... While reducing GHG production can be readily accomplished, doing so and maintaining production and feed efficiency has been much more difficult to achieve. Roque et al. [1] determined that seaweed (Asparagopsis) reduced CH 4 production by 67% when fed at 1% of the diet, but this substance also reduced intake and milk production. In the study of van Zijderfeld et al. [2] nitrate reduced CH 4 production by 40% but has the potential to be toxic. ...
... While great progress has been made and continues to be made on reconciling global methane sources and sinks, there are still many uncertainties (7,13,14). In particular, anthropogenic distortion of the natural methane cycle is a major contributor to climate change, yet new science-based technologies, such as animal feed additives (15) and rice paddy management practices (16), have the potential to reduce emissions. Furthermore, many questions remain regarding positive and negative feedbacks in the climate system, including feedbacks involving methane as a central player (17). ...
Methyl-based methanogenesis is one of three broad categories of archaeal anaerobic methanogenesis, including both the methyl dismutation (methylotrophic) pathway and the methyl-reducing (also known as hydrogen-dependent methylotrophic) pathway. Methyl-based methanogenesis is increasingly recognized as an important source of methane in a variety of environments. Here, we provide an overview of methyl-based methanogenesis research, including the conditions under which methyl-based methanogenesis can be a dominant source of methane emissions, experimental methods for distinguishing different pathways of methane production, molecular details of the biochemical pathways involved, and the genes and organisms involved in these processes. We also identify the current gaps in knowledge and present a genomic and metagenomic survey of methyl-based methanogenesis genes, highlighting the diversity of methyl-based methanogens at multiple taxonomic levels and the widespread distribution of known methyl-based methanogenesis genes and families across different environments.
... For example, a study showed that organic olives and crops had lower GHG emissions compared to conventional agriculture, while for cereals and pork this trend was reversed [8]. Proposed solutions for reducing GHG emissions from agricultural lands include (a) enhancing carbon sequestration by reducing erosion and tillage, giving priority to free range [9], applying biosolids, using periodic green fallows and the establishment of hedgerows, which can sequester and store carbon in their biomass, as well as in the soil [10][11][12], (b) reducing CH 4 production by reducing the use of concentrate in livestock diets [13], using CH 4 -inhibiting food supplement in the cow's gut, draining rice fields when flooding is not necessary and installing digesters to capture CH 4 produced during manure storage [14][15][16], (c) reducing N 2 O emission through moderate fertiliser application taking into account soil characteristics, the use of slow-release fertilisers or nitrification inhibitors and changes in the timing of application to improve absorption of nutrients by plants [17] and (d) increasing circularity of nutrients on farms by reintegrating crop and livestock systems and using a climate-smart pest management approach [18,19]. Reintegrating crop and livestock systems supposes benefits that can be economic (because of the utilisation of by-products on the other type of production) and environmental (e.g., because replacing synthetic fertilisers for organic ones improves soil structure and reduces GHG emissions) [20]. ...
Agricultural activities are important contributors to greenhouse gas (GHG) emissions in southern Chile. Three types of agricultural systems coexist within this region: traditional, conventional and agroecological. Historical changes in agricultural practices were identified from bibliographic sources and field surveys of 10 farms of each system type. A similarity analysis between systems was carried out using the survey data, which were also input to the Cool Farm Tool software to estimate GHG emissions of carbon dioxide, methane and nitrous oxide. The main historical changes identified were: (i) replacement of organic inputs by chemical products, (ii) replacement of workforce by agricultural machinery, (iii) decrease in crop diversity and (iv) decrease in total agricultural area. A multivariate analysis showed that agroecological systems are different from the traditional and conventional systems mainly because of the land use and the amount of organic fertiliser applied. However, no significant differences were found in the GHG emissions, which on average were 2999 ± 1521, 3443 ± 2376 and 3746 ± 1837 kg CO2-eq ha−1 year−1 (traditional, conventional and agroecological, respectively). Enteric fermentation was the main source of emissions in all agricultural systems, therefore methane was the most important GHG. Identifying the sources and practices that produce more emissions should help to improve management to reduce GHG emissions.
... Furthermore, an anti-methanogen vaccine is under development to reduce at least 20% of methane emissions from rumen [92,93]. Aquaculture and the seaweed industry are developing biotechnological solutions such as methane inhibitors and livestock productivity improvement [94,95] as well as sustainable fertilisers to reduce the use of synthetic fertilisers [24]. ...
There is a clear research gap in understanding how future pathways and disruptions to the New Zealand (NZ) agricultural system will have an impact on the environment and productivity. Agriculture is in a period of significant change due to market disruptions, climate change, increasingly stringent environmental regulations, and emerging technologies. In NZ, agriculture is a key sector of the economy, therefore government and industry need to develop policies and strategies to respond to the risks and opportunities associated with these disruptors. To address this gap, there is a need to develop an assessment tool to explore pathways and interventions for increasing agricultural profitability, resilience, and sustainability over the next 5–30 years. A decision support tool was developed through Stella Architect, bringing together production, market values, land use, water use, energy, fertiliser consumption, and emissions from agricultural sectors (dairy, beef, sheep, cereals, horticulture, and forests). The parameters are customisable by the user for scenario building. Two future trend scenarios (Business as usual, Optimisation and technology) and two breakaway scenarios (Carbon farming, Reduction in dairy demand) were simulated and all met carbon emissions goals, but profitability differed. Future environmental regulations can be met by adjusting levers associated with technology, carbon offsets, and land use. The model supports the development and assessment of pathways to achieve NZ’s national agriculture goals and has the potential to be scaled globally.
... [138]. Additionally, a different study found that using Asparagopsis armata algae at a rate of 0.5 to 1% of diet decreased CH 4 production by 43 to 60% [139]. However, the addition of macroalgae Ulva rigida, Gracilaria vermiculophylla, and Saccharina latissima to the amount of 25% of the rumen liquid has no effect on CH 4 reduction [140]. ...
Concerns about global warming and greenhouse gases have increased the interest of governments and the public sector to find solutions. To reduce the effects of global warming caused by greenhouse gases, especially methane, it is necessary to change animal production systems and adopt new strategic approaches. The reduction of enteric methane in livestock is a long-standing problem regarding the energy efficiency of consumed feed. In this review, the sources of production, dissemination, and introduction of accepted scientific and practical solutions in order to reduce methane gas in breeding and production units of dairy cows have been investigated. To carry out this research, a thorough search was conducted in articles published in valid databases between 1967 and 2022. A total of 213 articles were reviewed, and after screening, 159 were included in the study and analyzed using a PRISMA flow diagram. In general, low livestock efficiency, low-quality feed, a shortage of knowledge, and inadequate investment are the main causes of emission of these gases in poor or developing countries. On the other hand, developing countries may not always have access to the same methods that are utilized in industrialized countries to minimize the production of methane and other greenhouse gases like nitrous oxide. According to their conditions, developing countries should use the available tools to reduce methane production and emission, considering the costs, local knowledge, feasibility, and local laws. In future, there will be a greater need for interdisciplinary research to look for sustainable and acceptable methods for reducing methane emissions and other greenhouse gases from animal husbandry units, especially dairy cows. To change the population of rumen methanogens, as the main producers of methane, strategies such as feeding management, addition of inhibitors and vaccination are suggested. Also, there is a need for more applied research for reducing methane emissions.
... Several studies have reported that secondary bioactive compounds of seaweed have antiemthanogenic abilities [5]. Seaweed contains protein, carbohydrates, fats, vitamins, minerals, oils, amino acids, and other secondary compounds (phlorotannin, iodine, and halogenated compounds), which are beneficial for livestock health [6,7,8]. ...
This research was designed to evaluate the nutrient content of brown ( Laminaria Sp. and Padina australis ) and red algae ( Eucheuma cottonii and Gracilaria Sp.) from Kelapa beach, Tuban, East Java. The algae were cleaned from dirt and other materials before drying under the sun. All of the algae were ground and analyzed using proximate analysis (dry matter (DM), ash, organic matter (OM), ether extract (EE), crude protein (CP), crude fiber (CF), and nitrogen-free extract (NFE)) and gross energy with a bomb calorimeter. Data were analyzed descriptively by calculating the average of data obtained. The result showed that brown algae of Padina australis had the highest DM (30.59%) and CP (12.57%). The red algae of Eucheuma cottonii had the highest OM (76.58%), EE (2.85%), CF (8.80%), NFE (56.38%), and gross energy (2,911 Cal/g) but had the lowest DM (13.67%) and CP (8.55%). In opposite with Gracilaria sp. had the highest ash (65.63%) and the lowest OM (34.37%), EE (0.21%), CF (2.49%), NFE (19.95%) and gross energy (1,083 Cal/g). Based on this study, brown algae ( Laminaria sp and Padina australis ) and red algae ( Eucheuma cottonii and Gracilaria sp.) have the potential as ruminant feed, especially as mineral and soluble carbohydrate sources.
... The freeze-dried Asparagopsis (FD-Asp) has been the predominant technique to create the final Asparagopsis product used in methane mitigation studies to date. The effectiveness of freeze-dried Asparagopsis (FD-Asp) for methane mitigation has been consistently demonstrated in vitro Roque et al. 2019a) and in vivo using sheep (Li et al. 2018), dairy cows (Roque et al. 2019b), and beef steers (Kinley et al. 2020;Roque et al. 2021). A comprehensive review of these studies is available from Glasson et al. (2022). ...
The idea of delivering bromoform from Asparagopsis using edible oil has gained momentum recently due to the improved processing time and that it is already a feed that many livestock producers use. The stability of bromoform in oil compared to freeze-dried product is still not well understood. To fill this gap, a systematic study was carried out to determine the effects of storage temperatures (40 °C, 25 °C, 4 °C and -20 °C), fluorescent light and exposure to open air, on the retention of bromoform in freeze-dried Asparagopsis (FD-Asp) and Asparagopsis oil (Asp-Oil) over 24-week period. In the absence of fluorescent light, Asp-Oil was a more effective way to preserve bromoform compared to FD-Asp due to either no change or higher Asp-Oil bromoform content (storage temperature dependent) after 24-week storage. Under the same conditions, FD-Asp bromoform content decreased by 74% at 40 °C, 53% at 25 °C, 6% at 4 °C, and no change of FD-Asp bromoform content at -20 °C. The presence of fluorescent light negatively affected Asp-Oil bromoform content at both 25 °C and 40 °C while the effect was insignificant on FD-Asp. The exposure of Asp-Oil to open air resulted in the decrease of bromoform content to below quantification limit (0.18 mg g⁻¹) on week 8 for 40 °C sample and on week 16 for 25 °C sample. This study provides empirical evidence on the stabilising effect of oil in preserving bromoform extracted from Asparagopsis, confirming it is a more attractive medium to deliver bromoform compared to the freeze-dried powder form.
... Various other compounds found in seaweeds such as lipids, peptides and phlorotannins also play a role in reducing CH 4 emissions, although the modes of action are less understood (Machado et al., 2016;Abbott et al., 2020). Many studies have seen significant reductions in CH 4 emissions from livestock receiving seaweed-based additives at various administration rates and concentrations (Machado et al., 2016;Li et al., 2018;Roque et al., 2019;Kinley et al., 2020;Roque et al., 2021). However, there are concerns surrounding the potential for compounds such as iodine (toxic at high levels) and bromoform (carcinogen) to carry through the food chain and adversely affect human health (Antaya et al., 2019;Abbott et al., 2020). ...
The efficiency of Ireland’s grass-based livestock systems can be attributed to high outputs, low production costs and a low carbon footprint relative to housed systems. Methane (CH 4 ) is a potent greenhouse gas (GHG) of which enteric fermentation from livestock production is a key source, being directly responsible for 57% of Irish agricultural GHG emissions. There are a number of strategies including dietary manipulation and breeding initiatives that have shown promising results as potential mitigation solutions for ruminant livestock production. However, the majority of international research has predominantly been conducted on confined systems. Given the economic viability of Irish livestock systems, it is vital that any mitigation methods are assessed at pasture. Such research cannot be completed without access to suitable equipment for measuring CH 4 emissions at grazing. This review documents the current knowledge capacity in Ireland (publications and projects) and includes an inventory of equipment currently available to conduct research. A number of strategic research avenues are identified herein that warrant further investigation including breeding initiatives and dietary manipulation. It was notable that enteric CH 4 research seems to be lacking in Ireland as it constituted 14% of Irish agricultural GHG research publications from 2016 to 2021. A number of key infrastructural deficits were identified including respiration chambers (there are none currently operational in the Republic of Ireland) and an urgent need for more pasture-based GreenFeed™ systems. These deficits will need to be addressed to enable inventory refinement, research progression and the development of effective solutions to enteric CH 4 abatement in Ireland.
... For example, supplementation with red macroalgae Asparagopsis spp. has been shown to reduce CH4 emissions by upwards of 95% in vitro [41,42] and up to approximately 25-98% in ruminants in vivo [40,[43][44][45][46]. This occurs due to the fact that these macroalgae accumulate low-molecular-weight halogenated compounds (predominantly the brominated halomethane, bromoform) [41] that inhibit the methyl-coenzyme M reductase (MCR) enzyme, which catalyzes the ratelimiting and final step of the methanogenesis pathway, in rumen archaea [47]. ...
Rising emissions of anthropogenic greenhouse gases such as carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) are a key driver of climate change, which is predicted to have myriad detrimental consequences in coming years if not kept in check. Given the potency of CH4 in terms of trapping heat in the atmosphere in the short term, as well as the fact that ruminant production currently contributes approximately 30% of anthropogenic emissions, there is an impetus to substantially decrease the generation of ruminant-derived CH4. While various strategies are being assessed in this context, a multi-faceted approach is likely required to achieve significant reductions. Feed supplementation is one strategy that has shown promise in this field by attenuating methanogenesis in rumen archaea; however, this can be costly and sometimes impractical. In this review, we examine and discuss the prospect of directly modulating forages and/or rumen archaea themselves in a manner that would reduce methanogenesis using CRISPR/Cas-mediated gene editing platforms. Such an approach could provide a valuable alternative to supplementation and has the potential to contribute to the sustainability of agriculture, as well as the mitigation of climate change, in the future.
... It was demonstrated in studies that the use of Asparagopsis taxiformis in the diet of sheep has resulted in up to 80% reduction of methane emissions (Machado et al., 2016). Similar results have also been obtained with lactating dairy cows (Roque et al., 2019) and beef (Ridoutt et al., 2022). Apart from reducing methane emissions, other benefits of inclusion of seaweeds include higher mineral availability and increased digestibility. ...
Seaweeds have been utilized mainly for food, phycocolloid (agar, carrageenan and alginate) for more than a century. At global level, about 221 species are having commercial utility and among them, only 10 species are being commercially cultivated with the share of Eucheuma sp (35%), Laminaria japonica (27%), Gracilaria sp (13%), Undaria pinnadifida (8%) Kappaphycus alvarezii (6%), Porphyra sp (4%) and had a market value 11.7 billion US$ and recorded 27.3% of the whole marine aquaculture production (FAO, 2018). Among various seaweed based products, phycocolloids such as agar, carrageenan and alginates are major industrially important products because of the elevated demand due to their unique gelling, stabilizing and emulsifying characteristics. Seaweed's phycocolloids production was reached up to 93,035 tons wt in the year 2015 and had a market value of 1058 million US$ (Porse and Rudolph, 2017). The phycocolloid agar had higher market prices (US$ 18/kg) while comparing alginates (US$ 12/kg) and carrageenans (US$ 10.4/kg). Seaweeds are also being explored for animal feed and 3 rd generation biofuel. Though 844 species reported in India, only few seaweed species of such as Gelidiella acerosa, Gracilaria edulis, Sargassum sp and Turbinaria sp are commercially explored for agar and alginate production. Hypnea spp are being explored from natural resources and Kappaphycus alvarezii is being cultivated for kappa carrageenan production in India. Coastal rural population will earn their income either through natural seaweed resources collection or by cultivation.
... Other studies have tested various feed additives using a semi-continuous culture system with in vitro results being later con rmed in vivo. Roque et al. (2018) used the polypropylene RUSITEC vessels to test the effects of 5% DM Asparagopsis taxiformis on in vitro rumen fermentation and subsequent in vivo experiments showed similar rumen responses [23,24]. More recently, the effect of 3-Nitrooxypropanol (3-NOP) was explored in relation to changing concentrate ratios of feed rations for dairy cattle and the RUSITEC results [25] were supported in vivo [26]. ...
Background
The rumen contains a complex mixture of microbes, which are crucial for ruminant health and feed fermentation. During the fermentation process some of the feed-derived carbon becomes carbon dioxide and methane, which are released into the atmosphere where they act as greenhouse gases and contribute to climate change. There is growing interest in reducing the loss of feed-derived carbon and making it available to the animal, improving animal productivity, while also reducing the carbon footprint of the ruminant industry. To this end, artificial rumen systems (ARS) have been used for evaluating novel feed additives for their effect on the rumen microbiome and rumen function prior to conducting resource intensive animal trials. Whereas ARS are capable of predicting the response of the rumen and its microbiome, it is unclear how accurately different in vitro systems simulate the natural system and how results compare between the artificial systems that are being employed. Here we evaluated physical, chemical and microbiome metrics of three ARS over five days and compared them to those metrics in the in vivo rumen.
Results
Over a 48 hrs sampling period, the batch style platform (Ankom) was able to replicate pH, volatile fatty acid profile, and bacterial and fungal microbiome of the in vivo rumen, but its accuracy of mimicking in vivo metrics dropped significantly beyond 48 hrs. In contrast, the semi-continuous RUSITEC models, RUSITEC PP and RUSITEC prime, were able to mimic the volatile fatty acid profile and microbiota of the in vivo rumen for up to 120 hrs of rumen simulation. Comparison of gas production across vessel types demonstrated that the semi-continuous RUSITEC platforms display less variability among vessel replicates and time compared to the Ankom system.
Conclusions
In this study, we found that three widely used ARS were able to simulate the rumen ecosystem adequately for the first 48 hrs, with predictions from the more advanced semi-continuous ARS being more accurate when simulations extended over 48 hrs. Findings of this study will help to select the appropriate in vitro system for evaluating the response of the complex rumen microbiome to feed additives. Further work is necessary to improve the capabilities of these platforms and to standardize the methodology for large-scale application.
... Las algas marinas, también conocidas como macroalgas, incluyendo las marrones (Phaeophyta), rojas (Rhodophyta) y (Rhodophyta) y verdes (Chlorophyta), se han convertido en aditivos alimentarios preferibles por sus propiedades antimetanogénicas (Vijn et al., 2020;Roque et al., 2021). Varios estudios in vitro de suplementos de algas marinas mostraron una correlación negativa con la generación de metano especialmente con Asparagopsis taxiformis (Abbott et al., 2020;Maia, 2016;Min et al., 2021) y sus compañeras Asparagopsis sppreduce la emisión de metano in vivo del 50% a más del 80% en el ganado lechero (Roque et al., 2019;Li Bañuelos-Valenzuela y Delgadillo-Ruiz et al., 2016). Los prebióticos como el quitosano, la inulina y los productos de levadura también pueden limitar las emisiones de metano entérico modificando la estructura de la comunidad bacteriana del rumen (Tong et al., 2020;Seankamsorn et al., 2020). ...
... According to in vitro experiment, the fermented seaweed could stimulate the ruminant digestion, which significantly minimized the production of methane gas Klinger, 2021;Maia et al., 2016), and adding just 2% of particular seaweed species to the feed of cattle could potentially decrease the ruminant methane emission of up to 99% . According to Roque et al. (2019) in the lab integrating only 5% organic component of Asparagopsis (Rhodophyta) into the feedstock could decrease the emission by up to 95%. In the case of agriculture, the use of highly nutritive seaweed biochar (Zacharia et al., 2015) or compost seaweed (Cole et al., 2016) could improve crop productivity through the enhancement of soil quality and, as a result, emissions associated with artificial fertilizer manufacturing could be avoided (Smith, 2002). ...
Seaweed is a promising marine macroalgae of the millennium, providing various ecological, social, and economic benefits. At present, seaweed production reached 35.8 million t from farming, accounting for 97% of global seaweed output, with a world market of US$ 11.8 billion. Seaweeds are an excellent source of nutritious human food because of their low lipid content, high minerals, fibers, polyunsaturated fatty acids, polysaccharides, vitamins , and bioactive compounds. Many seaweed sub-products offer unique properties to develop various functional foods for the food processing industries. In the perspective of climate change mitigation, seaweed farms absorb carbon, serve as a CO 2 sink and reduce agricultural emissions by providing raw materials for biofuel production and livestock feed. Seaweed farming system also helps in climate change adaptation by absorbing wave energy, safeguarding shorelines, raising the pH of the surrounding water, and oxygenating the waters to minimize the impacts of ocean acidification and hypoxia on a localized scale. Moreover, it contributes substantially to the sustainable development of the economic condition of coastal women by providing livelihood opportunities and ensuring financial solvency. This review paper highlights the significance of seaweed farming in global food and nutritional security, mitigation and adaptation to global climate change, and women empowerment within a single frame. This review paper also outlined the major issues and challenges of seaweed farming for obtaining maximum benefits in these aspects. The main challenges of making seaweed as a staple diet to millions of people include producing suitable species of seaweeds, making seaweed products accessible, affordable, nutritionally balanced, and attractive to the consumers. Various food products must be developed from seaweeds that may be considered equivalent to the foods consumed by humans today. Lack of effective marine spatial planning to avoid user conflicts is vital for expanding the seaweed farming systems to provide aquatic foods and contribute globally for mitigation and adaptation of climate change impacts. Hence, women's empowerment through seaweed farming is primarily constrained by the lack of technical knowledge and financial resources to establish the coastal farming system. All the information discussed in this paper will help to understand the critical needs for large-scale seaweed farming for climate resilience mariculture, potentials for global food security, and future research on various aspects of seaweed farming and their diverse utilization.
... For example, the inclusion of the red seaweed Asparagopsis Taxiformis at a dietary dry matter level of just 0.2% yielded a methane reduction of 98% relative to a controlled beef steer group [9]. In another study, the inclusion of a closely related species Asparagopsis Armata in Holstein dairy cattle at a rate of 1% dry matter yielded a methane reduction of 67.2% [10]. Notably, these and other studies on seaweed feed supplementation reported simultaneous improvements in feed efficiency for beef cattle and milk production [11,12]. ...
This study provides an overview of both traditional nearshore seaweed farming infrastructure and more recent developments intended for large scale farming in more exposed coastal waters where nutrient supply may be a limiting factor. The success of multi-species integrated multi-trophic aquaculture (IMTA) methods predominantly in East Asia is a clear low cost path to scaling up seaweed cultivation in the broader world that provides for both synergistic sharing of nutrients and reduction in water eutrophication. A number of innovations intended to adapt farming methods to deeper or more exposed coastal waters and semi-automate cultivation steps promise to maintain the viability of farming in higher labour cost countries. Co-location of IMTA/finfish and seaweed farming with grid-connected offshore renewable energy (primarily offshore wind) shows the greatest synergistic benefits for marine space usage, decarbonisation, and nutrient management. Seaweed growth can be accelerated by cycling farm infrastructure between the near surface and nutrient richer depths or upwelling cooler nutrient rich water to sub-surface seaweed crops. Such systems would inevitably require significant increases in infrastructure complexity and costs, jeopardizing their economic viability. Combinations of seaweed and higher value aquaculture products may improve the viability of such novel systems.
... Similar reductions in methane production were observed in dairy cows that were fed 0.5 percent dry matter of Asparagopsis taxiformis, ranging from 55% to 80% [125]. Another study's in vivo results showed that cows' methane production dropped significantly by 26.4% at a low (0.5%) and 67.2% at a high (1%) level of Asparagopsis armata inclusion and bromoform concentration in milk, which was not significantly different between treatments [126]. A sheep study revealed that feeding up to 3% A. taxiformis to sheep reduced methane production in a dose-dependent way over a 72-day period, with an 80% reduction at the highest dose and no changes in body mass increase [127]. ...
Agriculture produces greenhouse gases. Methane is a result of manure degradation and microbial fermentation in the rumen. Reduced CH4 emissions will slow climate change and reduce greenhouse gas concentrations. This review compiled studies to evaluate the best ways to decrease methane emissions. Longer rumination times reduce methane emissions and milk methane. Other studies have not found this. Increasing propionate and reducing acetate and butyrate in the rumen can reduce hydrogen equivalents that would otherwise be transferred to methanogenesis. Diet can reduce methane emissions. Grain lowers rumen pH, increases propionate production, and decreases CH4 yield. Methane generation per unit of energy-corrected milk yield reduces with a higher-energy diet. Bioactive bromoform discovered in the red seaweed Asparagopsis taxiformis reduces livestock intestinal methane output by inhibiting its production. Essential oils, tannins, saponins, and flavonoids are anti-methanogenic. While it is true that plant extracts can assist in reducing methane emissions, it is crucial to remember to source and produce plants in a sustainable manner. Minimal lipid supplementation can reduce methane output by 20%, increasing energy density and animal productivity. Selecting low- CH4 cows may lower GHG emissions. These findings can lead to additional research to completely understand the impacts of methanogenesis suppression on rumen fermentation and post-absorptive metabolism, which could improve animal productivity and efficiency.
... and also increases milk yield (Habib and Khan 2018). In the case of lactating dairy cows, diet management can reduce enteric methane emissions by almost 60% (Roque et al. 2019). Similarly, a combination of hydrolysable tannin and condensed tannin at a concentration of 1.5% dietary dry matter helps reduce methane emissions from beef cattle without negatively affecting animal performance (Aboagye et al. 2018). ...
The agriculture sector in Asia and the Pacific region contributes massively to climate change, as the region has the largest share of greenhouse gas (GHG) emissions from agriculture. The region is the largest producer of rice, a major source of methane emissions. Further, to achieve food security for the increasing population, there has been a massive increase in the use of synthetic fertilizer and energy in agricultural production in the region over the last few decades. This has led to an enormous rise in nitrous oxide (N2O; mostly from fertilizer-N use) and carbon dioxide (mostly from energy use for irrigation) emissions from agriculture. Besides this, a substantial increase in livestock production for meat and dairy products has increased methane emissions, along with other environmental problems. In this context, this study conducts a systematic review of strategies that can reduce emissions from the agriculture sector using a multidimensional approach, looking at supply-side, demand-side, and cross-cutting measures. The review found that though there are huge potentials to reduce GHG emissions from agriculture, significant challenges exist in monitoring and verification of GHG emissions from supply-side measures, shifting to sustainable consumption behavior with regard to food consumption and use, and the design and implementation of regulatory and incentive mechanisms. On the supply side, policies should focus on the upscaling of climate-smart agriculture primarily through expanding knowledge and improving input use efficiency in agriculture, while on the demand side, there is a need to launch a drive to reduce food loss and waste and also to move towards sustainable consumption. Therefore, appropriate integration of policies at multiple levels, as well as application of multiple measures simultaneously, can increase mitigation potential as desired by the Paris Agreement and also help to achieve several of the United Nations' SDGs.
... Interestingly, Roque et al. (2021) reported a decrease of dry matter intake (DMI) by 14% with an equivalent increase in feed conversion efficiency in steers fed A. taxiformis (0.5% OM). A similar VOC containing species, A. armata, reduced CH 4 intensity (g/kg milk yield) by 60% and CH 4 yield by 43% when fed at 1% OM to lactating dairy cows (Roque et al., 2019). However, DMI was also decreased by 38% in that study. ...
Research is increasingly directed towards decreasing the greenhouse gases contribution, specifically methane, from the livestock agriculture sector. Macroalgae supplementation has emerged as a promising tool to mitigate enteric methane emission in ruminants. The mode of action responsible for the mitigation effect centers around the content of volatile halogenated compounds, primarily bromoform. The sub-tropical red seaweed, Asparagopsis taxiformis , is the most well researched bromoform containing species. While several studies, both in vitro and in vivo , have demonstrated the effectiveness of A. taxiformis at reducing enteric methane emission (> 80% reduction), questions surrounding sustainability, animal productivity, animal product quality, and commercial practicality remain. These questions by no means disqualify the practice of feeding macroalgae to cattle to reduce methane emission, but they must be answered before implementing macroalgae as a feed additive commercially. Also, limiting scientific inquiry to a few species reduces the potential of discovering other compounds and modes of action that could produce the desired mitigation effect without the inherit drawbacks of the current options. Work conducted in both ruminant nutrition and human health fields have identified numerous bioactive compounds within plants that exhibit anti-microbial functions that could modify the rumen microbiome for beneficial outcomes. These compounds are also found in macroalgae. Phlorotannins, saponins, sulfonated glycans, other halocarbons and bacteriocins found within macroalgae have demonstrated antimicrobial activity in vitro . However, it is unclear what effect these compounds may have when used in vivo . Once identified, extracting these compounds for supplementation in lieu of feeding the entire plant may be a more practical solution. Dietary inclusion levels of macroalgae in ruminant diets can be limited by variation in active ingredient concentration, palatability to cattle, and excessive dietary mineral content. There are multiple in vitro studies that have demonstrated a methane reduction potential of non-bromoform containing species, but inclusion levels are often well above the effective levels of A. taxiformis (< 0.5% of dietary dry matter). In some animal studies, A. taxiformis supplementation has led to decreased dry matter intake and productivity and elevated mineral accumulation, such as iodine, in animal products. Therefore, methane mitigation by macroalgae will likely have to occur at low dietary concentrations to be practical. This review aims to highlight potential benefits and challenges that feeding macroalgae as a tool for methane reduction may have on animal production, the environment, animal and consumer health.
... Studies by Machado et al. (2014) and Maia et al. (2016) noted high reduction of CH 4 in vitro, with inhibition of more than 90%. In support, feeding studies (Roque et al. 2019(Roque et al. , 2021 with dairy cows and beef steers respectively fed TMR-based diets observed CH 4 reduction of 26.4 vs 67.2% and 69 vs 80% and as a result of inclusion of seaweed (Asparagopsis spp) at rate of 0.5% vs 1.0% and 0.25 vs 0.5% respectively. Other aquatic plants with feeding possibilities are Azolla (i.e. ...
The Southern Africa Development Community (SADC) region is not a major emitter of greenhouse gases (GHG). However, Sub-Saharan Africa is considered a potential future hotspot for GHG emissions because of its large livestock population dispersed across large arid lands, coupled with the inherent low digestible feeds in the region and consequently low productivity of livestock. In SADC, climate change is predicted to increase temperatures further reducing agricultural productivity. Therefore, there is incentive to reduce agriculture’s contribution to GHG emissions in the SADC region. Ruminant production, a mainstay of rural economy, is predicted to decrease because of diminished grazing due to reduced rainfall and feed quality. However, ruminants’ enteric methane (CH4) production contributes to GHG emissions. This review explores strategies for the SADC region to reduce CH4 by ruminants. As methanogenesis is an outcome of microbial activity, potential opportunities include selecting animals with inherent low CH4 production; altering ruminal microbial populations to those that do not yield CH4; enhancing feed digestibility by feeding additives which improve diet quality and alter the ruminal microbiome and using specific forages such as seaweed or duckweed that contain plant secondary metabolites that may decrease methanogen populations or methanogenesis. These strategies are considered in terms of their potential magnitude of CH4 mitigation, the practicality for their implementation in the SADC region and their suitability to be included in the grazing-based livestock industries in the SADC region.
... Many researches have been conducted to determine the GHG reduction potential as a result of using seaweed in feed. In a study conducted byRoque et al. (2019) adding 0.5% and 1% of seaweed led to 27% and 67% reduction in methane intensity (per milk production). According to the results obtained byKinley et al. (2020), using 0.10% and 0.20% seaweed (Asparagopsis) as a feed ingredient, it can decrease the methane production up to 40% and 98%, and also can improve the weight gain by 53% and 42%, respectively.Roque et al. (2021)determined the impact of Asparagopsis taxiformis on methane production in growing beef steers. ...
Commissioned by the Dairy Working Group from the Sustainable Agriculture Initiative Platform (SAI Platform) and the European Roundtable for Beef Sustainability, an overview has been made based on literature research and a survey of 28 greenhouse gas mitigation options on dairy and beef farms and their degree of implementation. The mitigation options that have been implemented so far are mainly aiming at improving efficiency and productivity. A majority (63%) of respondents indicate that all or some of their supplying farmers know their individual carbon footprint. The big question is how to
stimulate farmers to implement mitigation options.
... The suppression of CH4 production by A. taxiformis has been previously documented by both in vitro and in vivo studies (Machado et al., 2015;Li et al., 2018;Roque et al., 2019b;Roque et al., 2019a;Abbott et al., 2020;Kinley et al., 2020). The present study also observed a rapid drop in CH4 production with A. taxiformis inclusion throughout the adaptation, intermediate, and stable phases compared to the control. ...
Several red seaweeds have shown to inhibit enteric CH4 production; however, adaptation of fermentation parameters to their presence is not well understood. The objective of this study was to examine the effect of three red seaweeds (Asparargopsis taxiformis, Mazzaella japonica, Palmaria mollis) on in vitro fermentation, CH4 production, and adaptation using the rumen simulation technique (RUSITEC). The experiment was conducted as a completely randomized design with four treatments, duplicated in two identical RUSITEC apparatus equipped with eight fermenter vessels each. The four treatments included the control (barley straw and barley silage) and the three red seaweeds added to the control diet at 2% diet DM. The experimental period was divided into four phases including a baseline phase (d 0-7; no seaweed included), adaptation phase (d 8-11; seaweed included in treatment vessels), intermediate phase (d 12-16) and a stable phase (d 17-21). The digestibility of organic matter (P = 0.04) and neutral detergent fibre (P = 0.05) was decreased by A. taxiformis during the adaptation phase, but returned to control levels in the stable phase. A. taxiformis supplementation resulted in a decrease (P < 0.001) in molar proportions of acetate, propionate and total volatile fatty acid (VFA) production, with an increase in molar proportions of butyrate, caproate, and valerate; the other seaweeds had no effect (P > 0.05) on molar proportions or production of individual VFA. A. taxiformis was the only seaweed to suppress CH4 production (P < 0.001), with the suppressive effect increasing (P < 0.001) across phases. Similarly, A. taxiformis increased (P < 0.001) the production of hydrogen (H2, %, mL/d) across the adaptation, intermediate and stable phases, with the intermediate and stable phases having greater H2 production than the adaptation phase. In conclusion, M. japonica and P. mollis did not impact rumen fermentation or inhibit CH4 production within the RUSITEC. In contrast, we conclude that A. taxiformis is an effective CH4 inhibitor and its introduction to the ruminal environment requires a period of adaptation; however, the large magnitude of CH4 suppression by A. taxiformis inhibits VFA synthesis, which may restrict production performance in vivo.
... For example, as the most effective macroalgae for CH 4 mitigation, red macroalgae Asparagopsis taxiformis reduced CH 4 production from 30.0% up to 69.0% when added from 0.5% to 3.0% (Almeida et al., 2021). But 38% dry matter intake reduction and milk production decline were observed when Asparagopsis was fed at 1% dry matter (Roque et al., 2019). A meta-analysis (24% studies trialed saponins, 50% fed tannins and 21% used essential oils) indicated 8%-14% CH 4 reduction through phytochemical supplementation compared with the control diet, with tannins and saponins having the greatest effect. ...
Methane emission from the ruminants is not only a significant amount of greenhouse gases contributing to climate change but also a reduction in feed efficacy. Mitigation of ruminal CH4 emission is a great challenge for cleaner livestock production. It is difficult to reduce CH4 production without any adverse effects on feed digestion. The present investigation was conducted to explore the sustainable mitigation of ruminal CH4 production with positive effects on feed digestibility using Neolamarckia cadamba leaves extract (NE). Stylo was added and ensiled with or without 1% and 2% NE, and the silage was engaged in vitro ruminal fermentation. Metagenomics was used to analyze the microbial communities and functional genes. The results indicated that the addition of 1% and 2% NE decreased (P < 0.001) CH4 production significantly and increased (P < 0.001) dry matter digestibility at the same time. The concentrations of volatile fatty acids were not altered by NE. Some genes related to glycoside hydrolases, glycosyl transferases, carbohydrate-binding modules were upregulated by 2%NE. The addition of NE showed little influence on the ruminal microbial community, but reduced (P < 0.05) the relative abundance of Methanobrevibacter, especially the Methanobrevibacter curvatus, which was positively correlated (correlation = 0.561, P = 0.011) with the ruminal CH4 production. In CH4 metabolism, genes related to the serine pathway were highly detected. The addition of NE inhibited (P < 0.05) CH4 metabolism by downregulating the great majority of involved genes. In conclusion, the present study provides new insights into the pathway of CH4 metabolism and useful information for understanding and controlling ruminal CH4 production in livestock production. The addition of NE might be a sustainable option to reduce CH4 while enhancing animal feed utilization efficiency. It could be used as a pronounced cleaner way for the ecosystem as well as livestock.
... Inclusión de Asparagopsis armata (rodofita) en la dieta de vacas lecheras lactantes reduce la emisión de metano entérico en más del 50% (Roque et al., 2019). ...
Resumen Las algas poseen aporte proteico, de minerales, fibra, antioxidantes, prebióticos e inmunoestimulantes, características importantes de un alimento para la nutrición animal. Existen evidencias sobre inclusiones de harina de algas, demostrando ser una materia prima alternativa para la formulación de alimentos, debido a su aporte al rendimiento, digestibilidad, mejora de parámetros de salud, incluso favorece aspectos sensoriales en la carne de las especies del sector ganadero. La zona costera de Ecuador alberga una gran diversidad de especies de algas, de las cuales se dispone de poca información, acerca de sus propiedades nutricionales; para su consumo en la dieta animal y otros fines industriales. Estudios recientes han demostrado lo factible que es el uso de las harinas de microalgas, siendo las más utilizadas las de Spirulina (Arthrospira sp.) y Chlorella sp. y así como también, las de macroalgas; tales como Rhodymenia howeana y Palmaria palmata (rodofitas); además de Ulva sp. (clorofita) y de Lessonia trabeculata y Laminaria digitata (feofita). La presente revisión conforma una integración de los avances tecnológicos sobre el uso directo y producción de biomasa algal como materia prima en la elaboración de balanceados para nutrición animal, en especies productivas del sector caprino, bovino, acuícola, avícola, porcícola y cunícola. Palabras clave: algas; balanceados; biomasa; materia prima; nutrición
... However, bromoform is a toxic compound and if used at higher doses for animal feeding, maybe secreted in milk, thus limiting its use in the dairy industry (Abbott et al. 2020). There is a need to establish a safety limit for bromoform in milk (Roque et al. 2019). ...
Treating livestock as senseless production machines has led to rampant depletion of natural resources, enhanced greenhouse gas emissions, gross animal welfare violations, and other ethical issues. it has essentially instigated constant scrutiny of conventional meat production by various experts and scientists. Sustainably in the meat sector is a big challenge which requires a multifaced and holistic approach. Novel tools like digitalization of the farming system and livestock market, precision livestock farming, application of remote sensing and artificial intelligence to manage production and environmental impact/GHG emission, can help in attaining sustainability in this sector. Further, improving nutrient use efficiency and recycling in feed and animal production through integration with agroecology and industrial ecology, improving individual animal and herd health by ensuring proper biosecurity measures and selective breeding, and welfare by mitigating animal stress during production are also key elements in achieving sustainability in meat production. in addition, sustainability bears a direct relationship with various social dimensions of meat production efficiency such as non-market attributes, balance between demand and consumption, market and policy failures. The present review critically examines the various aspects that significantly impact the efficiency and sustainability of meat production.
... Similarly in California, a decline in enteric CH 4 of 67.2 percent and 26.4 percent was observed when a very closely related species to A. taxiformis, Asparagopsis armata (A. Armata), a red algae, was fed to Holstein dairy cattle at April 30, 2022 simpsoncentre.ca 10 inclusion levels of 1 percent and 0.5 percent, respectively (Roque et al., 2019). No significant body weight change or milk yield difference between cows receiving A. armata at low inclusion compared to control; however, cattle receiving the 1 percent level gained 9.72 kg less than control cattle and produced 11.6 percent less milk. ...
The reduction of greenhouse gas emissions is a global goal across sectors. Methane, an especially potent greenhouse gas relative to carbon dioxide, is the target of the Global Methane Pledge, an undertaking by over 100 countries to reduce methane emissions by 30 percent by 2030. The agricultural sector is uniquely positioned to support Canadian methane reductions through mitigation of enteric fermentation in cattle. Enteric fermentation in dairy and beef cattle contribute to over 85 percent of methane emissions from the agriculture sector. Different mitigation strategies and technologies have demonstrated variable effect on methane reduction, depending on factors related to cattle diet, management, and operational practices. Relevant research and literature based on criteria related to potential application in western Canada and Canadian cattle production in the beef are dairy sector was collected and reviewed using PRISMA approach. Research in the beef and dairy sector were divided and compiled into separate databases to determine the most effective and impactful mitigation strategies. Overall, the use of 3NOP and marine algal strains as dietary additives were identified as the most promising technologies in reducing enteric fermentation, without negatively impacting production markers and subsequent profit. Tanniferous legumes as a forage also shows promise, however current findings in research demonstrate mixed effects on various production markers in dairy and beef cattle. Other mitigation strategies identified through the review process, including the use of various natural and synthetic dietary additives, require further investigation as inconclusive and insignificant results are predominant. To drive adoption of methane reduction strategies by farmers, introduction of the mitigation technologies and strategies discussed must align with Federal and Provincial policy development and implementation and ensure sufficient profit to producers, potentially through the sale of carbon offsets as the market development, in order to cover additional costs of adoption and incentivise use. Prompt introduction and adoption of the mitigation strategies discussed can effectively reduce enteric methane emissions in Canadian cattle herds, propelling Canada towards the 30 percent emission reduction goal in time for 2030.
... Advances in increasing the nutritional value of animal feed have increased signi cantly (de Morais & Costa 2007). For instance, Roque et al. (2019) investigated how seaweed can enhance the sustainability and health of cattle farming. Their study has further discovered that adding speci c seaweed varieties can help livestock to gain weight and also decrease greenhouse gases (methane) emissions by up to 67%. ...
This review examines global microalgae, seaweeds, and duckweed (MSD) production status and trends. It focuses on cultivation, recognizing the sector's existing and potential contributions and benefits, highlighting a variety of constraints and barriers over the sector's sustainable development. It also discusses lessons learned and ways forward to unlock the sector's full potential. In contrast to conventional agriculture crops, MSD can rapidly generate large amounts of biomass and carbon sequestration yet does not compete for arable land and potable water, ensuring minimal environmental impacts. Moreover, MSD's applications are ubiquitous and reach almost every industrial sector, including ones essential to meeting the increasing needs of human society, such as foods, pharmaceuticals, and chemicals. To this end, the growing public awareness regarding climate change, sustainable food, and animal welfare yields a significant shift in consumer preference and propels the demand for MSD. In addition, once governments usher in durable and stable carbon policies, the markets for MSD are likely to increase severalfold.
Expected final online publication date for the Annual Review of Resource Economics, Volume 14 is October 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Agricultural expansion to meet humanity’s growing needs for food and materials is a leading driver of land-use change, exacerbating climate change and biodiversity loss. Seaweed biomass farmed in the ocean could help reduce demand for terrestrial crops and reduce agricultural greenhouse gas emissions by providing a substitute or supplement for food, animal feed and biofuels. Here we model the global expansion potential of seaweed farming and explore how increased seaweed utilization under five different scenarios that consider dietary, livestock feed and fuel production seaweed usage may affect the environmental footprint of agriculture. For each scenario, we estimate the change in environmental impacts on land from increased seaweed adoption and map plausible marine farming expansion on the basis of 34 commercially important seaweed species. We show that ~650 million hectares of global ocean could support seaweed farms. Cultivating Asparagopsis for ruminant feed provided the highest greenhouse gas mitigation of the scenarios considered (~2.6 Gt CO2e yr−1). Substituting human diets at a rate of 10% globally is predicted to spare up to 110 million hectares of land. We illustrate that global production of seaweed has the potential to reduce the environmental impacts of terrestrial agriculture, but caution is needed to ensure that these challenges are not displaced from the land to the ocean. Seaweed farming could reduce agriculture’s environmental footprint, but its potential is not well-explored yet. This study shows how globally extended aquaculture can reduce terrestrial crops demand and greenhouse gas emissions while providing a substitute or supplement for food, animal feeds and fuel.
Methane (CH4) originating from enteric fermentation in ruminants, especially in cattle, is both an important greenhouse gas and causes a 12% loss in adult gross energy. Therefore, cost effective strategies are needed to reduce metagenesis in the ruminant production system. Recent studies have shown that the chemically synthesized compound 3-Nitrooxypropanol (3-NOP) has the potential to reduce enteric CH4 production by up to 30%. Asparagopsis taxiformis has proven to be a potent enteric CH4 inhibitor without affecting milk yield or nutrient utilization. However, there are some concerns that feeding seaweed to ruminants may lead to a spike in milk and/or meat bromoform content with potential implications for consumer health. The purpose of this review is to examine the general findings of in vivo and in vitro studies showing the efficacy of 3-NOP and red macroalgae.
The paper presents a review of different approaches to solving problems arising upon greenhouse gas emission from activities of animal husbandry enterprises. The sector of ruminant animal production is under close attention for ecological reasons due to its significant contribution to emission of enteric methane (CH4) and an effect on global climate change. Moreover, analysis of the main sources of methane emission in the agricultural sector of the agro-industrial complex, including by species of livestock and poultry, is given. An impact of a feeding system, feeds and feed additives in use and manure storage on nitrogen losses is estimated. In this connection, the authors examine several promising scientific and practical development results that are aimed to reducing emissions and formulating a strategy for controlling direct emissions of greenhouse gases in animal husbandry that do not jeopardize animal productivity, especially in the context of sustainability. Practical activities that envisage the development of the complex of measures for reduction of greenhouse gas emissions are examined. Potential strategies for mitigating their consequences were divided into the following main categories: animal raising, changes in animal diets and manipulations with rumen. Furthermore, several other measures facilitating an increase in livestock productivity and reduction of the negative effect on the environment were taken. Eco-economic methods for assessing emissions of harmful gases in production of animal husbandry products are considered and the necessity of developing simpler cost-effective technologies for quantitative assessment of greenhouse gas emissions and a search for solutions to preserve favorable climate is emphasized. When assessing greenhouse gas emissions, the loss sizes and cumulative ecological damage are taken into account. Realization of strategies for emission reduction should lead to an increase in animal productivity and a decrease in the negative effect of animal husbandry on the environment.
Modern poultry production systems face numerous economic, environmental, and social sustainability challenges that threaten their viability and acceptability as a major source of animal protein. As scientists and producers scramble to find cost-effective and socially acceptable solutions to these challenges, the dietary use of marine macroalgae (seaweeds) could be an ingenious option. Indeed, the incredible array of nutritive and bioactive compounds present in these macroscopic marine organisms can be exploited as part of sustainable poultry production systems of the future. Incorporating seaweeds in poultry diets could enhance feed utilization efficiency, growth performance, bird health, meat stability and quality, and consumer and environmental health. Theoretically, these benefits are mediated through the putative antiviral, antibacterial, antifungal, antioxidant, anticarcinogenic, anti-inflammatory, anti-allergic, antithrombotic, neuroprotective, hypocholesterolemic, and hypoglycemic properties of seaweed bioactive compounds. Despite this huge potential, exploitation of seaweed for poultry production appears to be constrained by a variety of factors such as high fibre, phenolics, and ash content. In addition, conflicting findings are often reported when seaweeds or their extracts are used in poultry feeding trials. Therefore, the purpose of this review paper is to collate information on the production, phytochemical components, and nutritive value of different seaweed species. It provides an overview of in vivo effects of dietary seaweeds as measured by nutrient utilization efficiency, growth performance, and product quality and stability in poultry. The utility of dietary seaweeds in sustainable poultry production systems is explored, while gaps that require further research are highlighted. Finally, opportunities that exist for enhancing the utility of seaweeds as a vehicle for sustainable production of functional poultry products for better global food and nutrition security are presented.
Global population increase and climate change continue to present challenges to
the sustainability of the primary production of food. Among the efforts to address
the challenges, exploration of the use of seaweed as food is gaining
traction. World seaweed production has more than tripled since the turn of the
millennium, increasing from 10.6 million tonnes in 2000 to 35.8 million tonnes
in 2019. However, seaweed can bioaccumulate hazardous substances and carry
pathogens from its cultivation environment. Several food safety hazards such as
heavy metals and marine biotoxins have been reported to be associated with the
commodity. The extent to which this translates into risks for public health remains
largely unexplored. Furthermore, food safety standards and legislation on seaweed
are generally lacking at both international and national levels. This FAO/WHO report discusses food safety of seaweed and makes recommendations for addressing identified challenges with a view to protect consumers and promote sustainable food security for all.
Within the increase of production, growth and technological developments related directly with increase in world population, demand for both fossil and renewable energy sources such as oil, coal, natural gas, nuclear and hydraulics is also increasing. Considering coal reserve values, it’s predicted that technological developments in global coal production and consumption will continue. Although coal-based electricity production has decreased in Turkey according to the precautions taken in line with greenhouse gas emissions, it’s expected to comply with trend of increase in energy supply around the world. Due to its economic worth and nature of the production process, mining is the most risky sector. On a European basis, observed that 59% of the mining sector deaths occurred in Turkey. In this study, the dimensions of occupational accidents that occurred for 17 different European countries at agriculture, production, construction, mining and other sectors were analyzed between 2009 and 2019. by using ILOSTAT data. Turkey has been the country with the highest loss in all sectors except agriculture. Considering the risk of occupational accidents, Turkey, Germany, Czech Republic, and Poland data, that have coal production were analyzed statistically with Latin Square Design layout using year, country and sector variables, by using General Linear Model. Single and binary interactions of variables (p
Introduction
The Nutrient Requirements of Dairy Cattle (NASEM, 2021) describes nutrient requirement as the daily amount of a specific nutrient necessary to meet a healthy cow’s needs for maintenance, activity, growth, reproduction, and lactation without changing the body reserves. It is well known that the nutrient requirements for pregnant cows were established from experiments conducted in the 1990s or earlier (Bell et al., 1995). Given the intensive selection for milk production, research has suggested that a modern dairy cow has greater metabolic rates than before (NASEM, 2021). The eighth revised edition of NASEM (2021) used the previous edition as the starting point, but the method to estimate pregnancy requirements was modified, considering that gestation must be accounted for when the cow is between 12 and 280 days of gestation (DG). Because NASEM (2021) was just released, comparisons with NRC, 2001, INRA, 2018 are still relevant. Furthermore, studies evaluating nutrient requirements for pregnant cows are scarce, and more research is warranted. Therefore, the objective of the present study was to estimate the protein requirements for maintenance, body gain, and gestation of Holstein × Gyr (HG) crossbred cows.
Material and Methods
Sixty-two Holstein × Gyr cows were used, with an average initial BW of 480 ± 10.1 kg and 5 ± 0.5 yrs of age. Cows were divided into three groups: pregnant (n = 44), non-pregnant (n = 12), and baseline (n = 6). Baseline animals were slaughtered before starting the experiment to estimate the initial body composition of the remaining animals. Pregnant and non-pregnant cows received two diets: maintenance and ad libitum. Pregnant cows were slaughtered at 139, 199, 241, and 268 days of pregnancy. First, we used data from non-pregnant cows to determine requirements for maintenance and growth in adult cows. Requirements of metabolizable protein for maintenance (MPm; g/EBW0.75/day) were estimated using a linear regression between the metabolizable protein intake (MPI, g/day) and average daily gain (g/day), and MPm was defined as the intercept divided by BW0.75. Net protein requirements for gain (NPg; g/day) were estimated by the first derivative of the allometric equation between final CP in the body (kg) and the final EBW (kg). The efficiency of use of metabolizable protein (k) was calculated from the regression between the retained protein (g/EBW0.75/day) and the MPI (g/EBW0.75/day), and k was the slope of this regression. The MPI was estimated by summing digestible microbial protein and digestible rumen undegradable protein. Secondly, we used data from all animals to determine pregnancy requirements for adult cows. An exponential model was used to fit the protein accumulation in the gestational components in the function of DG. The first derivative of that model was considered the net requirement for pregnancy (NPgest). The efficiency of protein utilization for gestation (kgest) was calculated by the iterative method using the equation: Δ = MPI − (MPm + NPg/kg + NPgest/kgest). The iteration was performed aiming at a zero deviation between observed MPI and MP estimated by the requirements determined herein. The linear regression parameters were estimated using PROC MIXED of SAS (version 9.4). Estimates of the parameters of non-linear regressions were adjusted using the PROC NLMIXED of SAS. Significances were declared when P < 0.05.
Results and Discussion
We obtained a value of 3.6 g/EBW0.75/day for MPm. The INRA (2018) suggests 2.2 g/EBW0.75/day for MPm, 38% lower than the present study. The estimation of NPg was calculated according to the following equation: NPg = 0.8095 × 0.732 × (EBWopen−0.268) × EBGcorrected, where EBWopen is the empty BW (kg) for non-pregnant animals and EBGcorrected is the empty body gain (kg/day) corrected for the gestational component. Using the equation proposed by NRC (2001) and taking into account a cow with 450 kg BW and a 0.3 kg/day of ADG, the estimated NPg would be 43 g/day. Our equation suggests an NPg of 35 g/day (18% lower) using the same animal. The k was 0.353, which is 22% higher than NRC (2001) suggested for dairy cows with BW greater than 478 kg. The net protein requirements for gestation (NPgest) were determined as NPgest (g/day) = 0.1767 × exp (0.02666 × DG) (Figure 1). The efficiency of using metabolizable protein for gestation (kgest) was 0.653. Overall, from 140 to 275 DG, our estimates of MPgest were 30% lower than those described by NASEM (2021), while the INRA (2018) underestimated MPgest of crossbred cows by 36%.
Conclusion and Implications
The proposed equations to estimate the protein requirements for HG pregnant cows were different from those reported by INRA, 2018, NRC, 2001, and NASEM (2021). We recommend using our equations to estimate protein requirements for maintenance, growth, and pregnancy of HG dairy cows.
This paper analyzes the mitigation of enteric methane (CH4) emissions from ruminants with the use of feed additives inhibiting of rumen methanogenesis to limit global temperature increase to 1.5 °C. A mathematical simulation conducted herein predicted that pronounced inhibition of rumen methanogenesis with pure chemicals or bromoform-containing algae can contribute to limit global temperature increase by 2050 to 1.5 °C only if widely adopted at a global level and considering an efficacy higher than obtained in most studies. Currently, the most important limitations to the adoption of antimethanogenic feed additives are probably increased feeding cost without a consistent return in production efficiency, and achieving sustained delivery of inhibitors to the rumens of non-supplemented, extensively ranging animals. Economic incentives, and changes in rumen microbial metabolism caused by inhibiting methanogenesis, could potentially be used to make the methanogenesis inhibition intervention cost effective. Also, the composition of the methanogenic community, and rate of disappearance of inhibitors of methanogenesis in the rumen can influence the effective dose of the inhibitors, and hence the cost of their adoption. Possible means for sustained delivery of antimethanogenic compounds to extensively grazing animals are discussed. Limitations and knowledge gaps of these approaches, and future research directions, are examined.
[This corrects the article DOI: 10.1371/journal.pone.0161362.].
This study is the first to evaluate the effects of five seaweeds (Ulva sp., Laminaria ochroleuca, Saccharina latissima, Gigartina sp., and Gracilaria vermiculophylla) on gas and methane production and ruminal fermentation parameters when incubated in vitro with two substrates (meadow hay and corn silage) for 24 h. Seaweeds led to lower gas production, with Gigartina sp. presenting the lowest value. When incubated with meadow hay, Ulva sp., Gigartina sp. and G. vermiculophylla decreased methane production, but with corn silage, methane production was only decreased by G. vermiculophylla. With meadow hay, L. ochroleuca and S. latissima promoted similar methane production as the control, but with corn silage, L. ochroleuca increased it. With the exception of S. latissima, all seaweeds promoted similar levels of total volatile fatty acid production. The highest proportion of acetic acid was produced with Ulva sp., G. vermiculophylla, and S. latissima; the highest proportion of butyric acid with the control and L. ochroleuca; and the highest proportion of iso-valeric acid with Gigartina sp. These results reveal the potential of seaweeds to mitigate ruminal methane production and the importance of the basal diet. To efficiently use seaweeds as feed ingredients with nutritional and environmental benefits, more research is required to determine the mechanisms underlying seaweed and substrate interactions.
Asparagopsis taxiformis concentrates halogenated compounds which are known to inhibit cobamide-dependent methanogenesis in vitro and therefore has potential to mitigate enteric methane production. This study investigated the effect of Asparagopsis on methane (CH4) production from sheep offered a high fibre pelleted diet (offered at 1.2 x30 maintenance) at five levels of Asparagopsis for 72 d (0% (control), 0.5%, 1%, 2% and 3% organic matter -OM basis as offered ). Individual animal methane measurements were conducted at 21 d intervals using pen circuit respiration chambers. Asparagopsis inclusion resulted in a consistent and dose dependent reduction in enteric methane production over time, with up to 80% methane mitigation at the 3% offered rate compared with the group fed no Asparagopsis (P < 0.05). Sheep fed Asparagopsis had significantly lower concentration of total volatile fatty acids and acetate, but higher propionate concentration. No changes in live weight gain were identified. Supplementing Asparagopsis in a high fiber diet (< 2% OM) results in significant and persistent decreases in enteric methanogenesis over a 72 d period. Granulomatous and keratotic ruminal mucosa changes were identified in several sheep with Asparagopsis supplementation. While the outcomes of this study may be extrapolated to feedlot to achieve the antimethanogenic effect associated with Asparagopsis, further work is required to define the long term effects on productivity and animal health.
Significance
Methane emission from the ruminant livestock sector—a by-product from enteric fermentation of plant biomass in the ruminant digestive system—is produced by methanogenic archaea and represents not only a significant amount of anthropogenic greenhouse gases contributing to climate change but also an energy loss and a reduction in feed efficacy. The present study elucidates the development and the unique mode of action of the highly specific inhibitor 3-nitrooxypropanol (3-NOP), which is targeting the nickel enzyme methyl-coenzyme M reductase in rumen archaea that catalyzes the methane-forming reaction. At the very low effective concentrations recently applied in vivo (dairy and beef cattle), 3-NOP appears to inhibit only methanogens and thus to be attractive for development as a feed supplement.
Asparagopsis taxiformis has potent antimethanogenic activity as a feed supplement at 2 % of organic matter in in vitro bioassays. This study identified the main bioactive natural products and their effects on fermentation using rumen fluid from Bos indicus steers. Polar through to non-polar extracts (water, methanol, dichloromethane and hexane) were tested. The dichloromethane extract was most active, reducing methane production by 79 %. Bromoform was the most abundant natural product in the biomass of Asparagopsis (1723 μg g−1 dry weight [DW] biomass), followed by dibromochloromethane (15.8 μg g−1 DW), bromochloroacetic acid (9.8 μg g−1 DW) and dibromoacetic acid (0.9 μg g−1 DW). Bromoform and dibromochloromethane had the highest activity with concentrations ≥1 μM inhibiting methane production. However, only bromoform was present in sufficient quantities in the biomass at 2 % organic matter to elicit this effect. Importantly, the degradability of organic matter and volatile fatty acids were not affected at effective concentrations.
Livestock feed modification is a viable method for reducing methane emissions from ruminant livestock. Ruminant enteric methane is responsible approximately to 10% of greenhouse gas emissions in Australia. Some species of macroalgae have antimethanogenic activity on in vitro fermentation. This study used in vitro fermentation with rumen inoculum to characterise increasing inclusion rates of the red macroalga Asparagopsis taxiformis on enteric methane production and digestive efficiency throughout 72-h fermentations. At dose levels ≤1% of substrate organic matter there was minimal effect on gas and methane production. However, inclusion ≥2% reduced gas and eliminated methane production in the fermentations indicating a minimum inhibitory dose level. There was no negative impact on substrate digestibility for macroalgae inclusion ≤5%, however, a significant reduction was observed with 10% inclusion. Total volatile fatty acids were not significantly affected with 2% inclusion and the acetate levels were reduced in favour of increased propionate and, to a lesser extent, butyrate which increased linearly with increasing dose levels. A barrier to commercialisation of Asparagopsis is the mass production of this specific macroalgal biomass at a scale to provide supplementation to livestock. Another area requiring characterisation is the most appropriate method for processing (dehydration) and feeding to livestock in systems with variable feed quality and content. The in vitro assessment method used here clearly demonstrated that Asparagopsis can inhibit methanogenesis at very low inclusion levels whereas the effect in vivo has yet to be confirmed.
Japanese goats fed a diet of 50% Timothy grass and 50% concentrate with increasing levels of the anti-methanogenic compound, bromochloromethane (BCM) were investigated with respect to the microbial population and functional shifts in the rumen. Microbial ecology methods identified species that exhibited positive and negative responses to the increasing levels of BCM. The methane-inhibited rumen appeared to adapt to the higher H2 levels by shifting fermentation to propionate which was mediated by an increase in the population of H2-consuming Prevotella and Selenomonas spp. Metagenomic analysis of propionate production pathways was dominated by genomic content from these species. Reductive acetogenic marker gene libraries and metagenomics analysis indicate that reductive acetogenic species do not play a major role in the BCM treated rumen.
Significance
Methane from enteric fermentation in the ruminant digestive system is a major contributor to anthropogenic greenhouse gas emissions in the United States and worldwide. Methane is also a net loss of feed energy to the animal. This study was undertaken to investigate the effect of a methane inhibitor on enteric methane emissions from lactating dairy cows. The experiment demonstrated that, under industry-relevant conditions, the inhibitor persistently decreased by 30% enteric methane emissions, without negatively affecting animal productivity. The spared methane energy was partially used for tissue synthesis, which led to a greater body weight gain by the inhibitor-treated cows. If adopted, this mitigation practice could lead to a substantial reduction of greenhouse gas emissions from the ruminant livestock sector.
This study aimed to identify the optimal doses of the macroalgae Asparagopsis taxiformis and Oedogonium sp., individually and in combination, which would decrease the in vitro production of methane while minimizing adverse effects on fermentation, using rumen inoculant from Bos indicus steers. The dose-response experiment evaluated ten doses of Asparagopsis [ranging from 0 to 16.7 % of the organic matter (OM) incubated] and seven doses of Oedogonium (ranging from 0 to 100 % OM) using Rhodes grass hay as a basal substrate. Asparagopsis was highly effective in decreasing the production of methane with a reduction of 99 % at doses as low as 2 % OM basis. However, a dose of 2 % OM also decreased the production of volatile fatty acids (VFA). Oedogonium was less effective with doses ≥50 % OM significantly decreasing the production of methane. A combination of Asparagopsis (2 % OM) and Oedogonium (25 and 50 % OM) continued to suppress the production of methane, independent of the inclusion rate of Oedogonium. The effectiveness of Asparagopsis demonstrates its potential for the mitigation of methane emissions from ruminants at inclusion rates of ≤2 % OM. Oedogonium is a potential feed supplement due to its nutritional value, but supplements ≤25 % OM are recommended to avoid adverse effects on apparent in vitro fermentation.
Algae have become an area of intensive research in many fields of study. Areas of application are becoming increasingly diverse with the advent of technologies particularly in the mass production of algae biomass. Algae contain complex bioactive compounds and these are gaining importance in emerging technologies with nutritional and environmental applications. In this study, a preliminary investigation evaluated 15 species of algae from the major categories of marine and fresh water algae for their potential as inclusions in ruminant diets for management of greenhouse gas emissions. It was hypothesized that algae would positively affect rumen fermentation and gas production while reducing methane production. The hypothesis was tested using an Ankom automated gas monitoring system and rumen fluid from Bos indicus steers fed tropical forage diets. The results were variable between algae species with some showing a significant reduction in total gas and methane production, with others increasing gas and fermentation. The red and brown algae stand out as having potential for greenhouse gas mitigation with the brown alga Cystoseira having the most prominent effect. The effects observed on fermentation may be manipulated through dosage management and beneficial effects could be potentially maximized by preparing combinations of algal supplements. It has been demonstrated in this study that algae have the potential to assist in rumen fermentation management for improved gas production, and greenhouse gas abatement.
Grape marc (the skins, seeds, stalk, and stems remaining after grapes have been pressed to make wine) is currently a by-product used as a feed supplement by the dairy and beef industries. Grape marc contains condensed tannins and has high concentrations of crude fat; both these substances can reduce enteric methane (CH4) production when fed to ruminants. This experiment examined the effects of dietary supplementation with either dried, pelleted grape marc or ensiled grape marc on yield and composition of milk, enteric CH4 emissions, and ruminal microbiota in dairy cows. Thirty-two Holstein dairy cows in late lactation were offered 1 of 3 diets: a control (CON) diet; a diet containing dried, pelleted grape marc (DGM); and a diet containing ensiled grape marc (EGM). The diet offered to cows in the CON group contained 14.0 kg of alfalfa hay dry matter (DM)/d and 4.3 kg of concentrate mix DM/d. Diets offered to cows in the DGM and EGM groups contained 9.0 kg of alfalfa hay DM/d, 4.3 kg of concentrate mix DM/d, and 5.0 kg of dried or ensiled grape marc DM/d, respectively. These diets were offered individually to cows for 18 d. Individual cow feed intake and milk yield were measured daily and milk composition measured on 4 d/wk. Individual cow CH4 emissions were measured by the SF6 tracer technique on 2 d at the end of the experiment. Ruminal bacterial, archaeal, fungal, and protozoan communities were quantified on the last day of the experiment. Cows offered the CON, DGM, and EGM diets, ate 95, 98, and 96%, respectively, of the DM offered. The mean milk yield of cows fed the EGM diet was 12.8 kg/cow per day and was less than that of cows fed either the CON diet (14.6 kg/cow per day) or the DGM diet (15.4 kg/cow per day). Feeding DGM and EGM diets was associated with decreased milk fat yields, lower concentrations of saturated fatty acids, and enhanced concentrations of mono- and polyunsaturated fatty acids, in particular cis-9,trans-11 linoleic acid. The mean CH4 emissions were 470, 375, and 389 g of CH4/cow per day for cows fed the CON, DGM, and EGM diets, respectively. Methane yields were 26.1, 20.2, and 21.5 g of CH4/kg of DMI for cows fed the CON, DGM, and EGM diets, respectively. The ruminal bacterial and archaeal communities were altered by dietary supplementation with grape marc, but ruminal fungal and protozoan communities were not. Decreases of approximately 20% in CH4 emissions and CH4 yield indicate that feeding DGM and EGM could play a role in CH4 abatement.
Many opportunities exist to reduce enteric methane (CH4) and other greenhouse gas (GHG) emissions per unit of product from ruminant livestock. Research over the past century in genetics, animal health, microbiology, nutrition, and physiology has led to improvements in dairy production where intensively managed farms have GHG emissions as low as 1 kg of CO2 equivalents (CO2e)/kg of energy-corrected milk (ECM), compared with >7 kg of CO2e/kg of ECM in extensive systems. The objectives of this review are to evaluate options that have been demonstrated to mitigate enteric CH4 emissions per unit of ECM (CH4/ECM) from dairy cattle on a quantitative basis and in a sustained manner and to integrate approaches in genetics, feeding and nutrition, physiology, and health to emphasize why herd productivity, not individual animal productivity, is important to environmental sustainability. A nutrition model based on carbohydrate digestion was used to evaluate the effect of feeding and nutrition strategies on CH4/ECM, and a meta-analysis was conducted to quantify the effects of lipid supplementation on CH4/ECM. A second model combining herd structure dynamics and production level was used to estimate the effect of genetic and management strategies that increase milk yield and reduce culling on CH4/ECM. Some of these approaches discussed require further research, but many could be implemented now. Past efforts in CH4 mitigation have largely focused on identifying and evaluating CH4 mitigation approaches based on nutrition, feeding, and modifications of rumen function. Nutrition and feeding approaches may be able to reduce CH4/ECM by 2.5 to 15%, whereas rumen modifiers have had very little success in terms of sustained CH4 reductions without compromising milk production. More significant reductions of 15 to 30% CH4/ECM can be achieved by combinations of genetic and management approaches, including improvements in heat abatement, disease and fertility management, performance-enhancing technologies, and facility design to increase feed efficiency and life-time productivity of individual animals and herds. Many of the approaches discussed are only partially additive, and all approaches to reducing enteric CH4 emissions should consider the economic impacts on farm profitability and the relationships between enteric CH4 and other GHG.
This study aimed to evaluate the effects of twenty species of tropical macroalgae on in vitro fermentation parameters, total gas production (TGP) and methane (CH4) production when incubated in rumen fluid from cattle fed a low quality roughage diet. Primary biochemical parameters of macroalgae were characterized and included proximate, elemental, and fatty acid (FAME) analysis. Macroalgae and the control, decorticated cottonseed meal (DCS), were incubated in vitro for 72 h, where gas production was continuously monitored. Post-fermentation parameters, including CH4 production, pH, ammonia, apparent organic matter degradability (OMd), and volatile fatty acid (VFA) concentrations were measured. All species of macroalgae had lower TGP and CH4 production than DCS. Dictyota and Asparagopsis had the strongest effects, inhibiting TGP by 53.2% and 61.8%, and CH4 production by 92.2% and 98.9% after 72 h, respectively. Both species also resulted in the lowest total VFA concentration, and the highest molar concentration of propionate among all species analysed, indicating that anaerobic fermentation was affected. Overall, there were no strong relationships between TGP or CH4 production and the >70 biochemical parameters analysed. However, zinc concentrations >0.10 g.kg(-1) may potentially interact with other biochemical components to influence TGP and CH4 production. The lack of relationship between the primary biochemistry of species and gas parameters suggests that significant decreases in TGP and CH4 production are associated with secondary metabolites produced by effective macroalgae. The most effective species, Asparagopsis, offers the most promising alternative for mitigation of enteric CH4 emissions.
Agriculture has a key role in food production worldwide and it is a major component of the gross domestic product of several countries. Livestock production is essential for the generation of high quality protein foods and the delivery of foods in regions where animal products are the main food source. Environmental impacts of livestock production have been examined for decades, but recently emission of methane from enteric fermentation has been targeted as a substantial greenhouse gas source. The quantification of methane emissions from livestock on a global scale relies on prediction models because measurements require specialized equipment and may be expensive. The predictive ability of current methane emission models remains poor. Moreover, the availability of information on livestock production systems has increased substantially over the years enabling the development of more detailed methane prediction models. In this study, we have developed and evaluated prediction models based on a large database of enteric methane emissions from North American dairy and beef cattle. Most probable models of various complexity levels were identified using a Bayesian model selection procedure and were fitted under a hierarchical setting. Energy intake, dietary fiber and lipid proportions, animal body weight and milk fat proportion were identified as key explanatory variables for predicting emissions. Models here developed substantially outperformed models currently used in national greenhouse gas inventories. Additionally, estimates of repeatability of methane emissions were lower than the ones from the literature and multicollinearity diagnostics suggested that prediction models are stable. In this context, we propose various enteric methane prediction models which require different levels of information availability and can be readily implemented in national greenhouse gas inventories of different complexity levels. The utilization of such models may reduce errors associated with prediction of methane and allow a better examination and representation of policies regulating emissions from cattle. This article is protected by copyright. All rights reserved.
Early scientific studies conducted at the turn of the twentieth century failed to support the inclusion of seaweeds into animal rations at high inclusion rates. At that time, based on proximate analysis and energy availability studies, dried seaweeds or kelp meal largely fell out of favor as a recommended animal feed source. Nevertheless, kelp meal was still regarded by some as having properties which improved animal health and productivity which were not conveniently explained by conventional feed analysis. In the 1970s, research leads to the discovery that chelated micromineral sources were more efficient for the delivery of microelements than conventional inorganic sources. This prompted renewed interest in seaweeds as rich sources of over 60+ microelements. However, it was only in the early 2000s, when detailed analysis of the complex structure of the polysaccharides associated with seaweeds was tied to their prebiotic actions, that a clear explanation for the basis of productivity and health enhancement was attained. Further analysis indicated that other constituents in various brown seaweeds such as phlorotannins and antioxidants also contributed to the observed bioactivities. Of all of the brown seaweeds cited in studies, the one most scientifically documented is Ascophyllum nodosum, and of all of these sources, Tasco®, a sundried, high-quality macroalgal product, produced by Acadian Seaplants has been the most studied. The latest studies of Tasco® suggest prebiotic potencies at least five times that of the reference prebiotic inulin with additional performance-enhancing benefits in animal rations that rival antibiotic inclusions.
The goal of this review was to analyze published data related to mitigation of enteric methane (CH4) emissions from ruminant animals to document the most effective and sustainable strategies. Increasing forage digestibility and digestible forage intake was one of the major recommended CH4 mitigation practices. Although responses vary, CH4 emissions can be reduced when corn silage replaces grass silage in the diet. Feeding legume silages could also lower CH4 emissions compared to grass silage due to their lower fiber concentration. Dietary lipids can be effective in reducing CH4 emissions, but their applicability will depend on effects on feed intake, fiber digestibility, production, and milk composition. Inclusion of concentrate feeds in the diet of ruminants will likely decrease CH4 emission intensity (Ei; CH4 per unit animal product), particularly when inclusion is above 40% of dietary dry matter and rumen function is not impaired. Supplementation of diets containing medium to poor quality forages with small amounts of concentrate feed will typically decrease CH4 Ei. Nitrates show promise as CH4 mitigation agents, but more studies are needed to fully understand their impact on whole-farm GHG emissions, animal productivity, and animal health. Through their effect on feed efficiency and rumen stoichiometry, ionophores are likely to have a moderate CH4 mitigating effect in ruminants fed high-grain or mixed grain-forage diets. Tannins may also reduce CH4 emissions, although in some situations intake and milk production may be compromised. Some direct-fed microbials, such as yeast-based products, might have a moderate CH4-mitigating effect through increasing animal productivity and feed efficiency, but the effect is likely to be inconsistent. Vaccines against rumen archaea may offer mitigation opportunities in the future, although the extent of CH4 reduction is likely to be small, and adaptation by ruminal microbes and persistence of the effect is unknown. Overall, improving forage quality and the overall efficiency of dietary nutrient use is an effective way of decreasing CH4 Ei. Several feed supplements have a potential to reduce CH4 emission from ruminants, although their long-term effect has not been well-established and some are toxic or may not be economically feasible.
Enteric fermentation has been estimated to be responsible for 64.2 Mt CO2-e, or ∼16% of Australia's greenhouse gas emissions (Australian Greenhouse Office 2007). A bromochloromethane (BCM) formulation, previously shown to inhibit methanogenesis, was included in the diet of Brahman (Bos indicus) cross steers, twice daily in three separate experiments, to determine the effect on methane production, daily feed intake, liveweight (LW) gain and accumulation of residues of BCM in edible tissue. In the first experiment, the BCM formulation was fed at rates of 0, 0.15, 0.30, or 0.60 g/100 kg LW, twice daily, for 28 days. Methane production (mean s.e.), measured over 11 h after feed was first consumed on day 28, was 0.3 0.13 and 0.1 0.03 L/h for animals treated at a rate of 0.30 and 0.60 g/100 kg LW, respectively. This was significantly less (P 0.05) than for control animals (4.6 0.46 L/h) and animals treated at a rate of 0.15 g/100 kg LW (2.1 0.28 L/h). The dose rate of 0.30 g/100 kg LW was associated with a decrease in methanogenesis by ∼93% compared with the control group and was used in subsequent experiments. The second experiment evaluated the efficacy of the BCM formulation fed at rates of 0 or 0.30 g/100 kg LW, twice daily, for 90 days. Methane production was measured over 24-h periods, on days 30, 60 and 90. For days 30 and 90, methane production was reduced by 60% (P 0.05) to 4.2 1.82 L/h and by 50% (P 0.05) to 6.1 0.63 L/h, respectively, for treated animals compared with the control group. The final experiment determined the effect on LW gain and detectable residues in edible tissue, with animals given the BCM formulation at rates of 0 or 0.30 g/100 kg LW, twice daily, for 85 days. Liver, kidney, depot fat and muscle samples collected 1 and 10 days after the last day of treatment had concentrations of BCM that did not exceed 0.015 mg/kg and were less than the temporary maximum residue limit (0.02 mg/kg BCM), which applies to bovine meat, fat and edible offal. There were no significant differences in LW gain (1.4 0.10 v. 1.5 0.07 kg/day), feed conversion ratio (5.7 0.32 v. 5.4 0.09), hot carcass weight (235 5.0 v. 250 6.5 kg) or P8 fat depth (6.4 0.89 v. 8.1 1.15 mm) between control and treated animals. The experiments reported here were completed in 2004 before the Australian Government prohibited the manufacture and use of BCM. It is unlikely that the BCM formulation will be available for commercial use to mitigate livestock methane emissions in Australia. Nevertheless, the study has demonstrated that methane emissions were substantially reduced over a 90-day feedlot finishing period. This indicates that alternative antimethanogens with a similar mechanism of action may have practical commercial relevance.
Monensin is a widely used feed additive with the potential to minimize methane (CH4) emissions from cattle. Several studies have investigated the effects of monensin on CH4, but findings have been inconsistent. The objective of the present study was to conduct meta-analyses to quantitatively summarize the effect of monensin on CH4 production (g/d) and the percentage of dietary gross energy lost as CH4 (Ym) in dairy cows and beef steers. Data from 22 controlled studies were used. Heterogeneity of the monensin effects were estimated using random effect models. Due to significant heterogeneity (>68%) in both dairy and beef studies, the random effect models were then extended to mixed effect models by including fixed effects of DMI, dietary nutrient contents, monensin dose, and length of monensin treatment period. Monensin reduced Ym from 5.97 to 5.43% and diets with greater neutral detergent fiber contents (g/kg of dry matter) tended to enhance the monensin effect on CH4 in beef steers. When adjusted for the neutral detergent fiber effect, monensin supplementation [average 32 mg/kg of dry matter intake (DMI)] reduced CH4 emissions from beef steers by 19 ± 4 g/d. Dietary ether extract content and DMI had a positive and a negative effect on monensin in dairy cows, respectively. When adjusted for these 2 effects in the final mixed-effect model, monensin feeding (average 21 mg/kg of DMI) was associated with a 6 ± 3 g/d reduction in CH4 emissions in dairy cows. When analyzed across dairy and beef cattle studies, DMI or monensin dose (mg/kg of DMI) tended to decrease or increase the effect of monensin in reducing methane emissions, respectively. Methane mitigation effects of monensin in dairy cows (-12 ± 6 g/d) and beef steers (-14 ± 6 g/d) became similar when adjusted for the monensin dose differences between dairy cow and beef steer studies. When adjusted for DMI differences, monensin reduced Ym in dairy cows (-0.23 ± 0.14) and beef steers (-0.33 ± 0.16). Monensin treatment period length did not significantly modify the monensin effects in dairy cow or beef steer studies. Overall, monensin had stronger antimethanogenic effects in beef steers than dairy cows, but the effects in dairy cows could potentially be improved by dietary composition modifications and increasing the monensin dose.
Vanadium haloperoxidases differ strongly from heme peroxidases in substrate specificity and stability and in contrast to a heme group they contain the bare metal oxide vanadate as a prosthetic group. These enzymes specifically oxidize halides in the presence of hydrogen peroxide into hypohalous acids. These reactive halogen intermediates will react rapidly and aspecifically with many organic molecules. Marine algae and diatoms containing these iodo- and bromoperoxidases produce short-lived brominated methanes (bromoform, CHBr3 and dibromomethane CH2Br2) or iodinated compounds. Some seas and oceans are supersaturated with these compounds and they form an important source of bromine to the troposphere and lower stratosphere and contribute significantly to the global budget of halogenated hydrocarbons. This perspective focuses, in particular, on the biosynthesis of these volatile compounds and the direct or indirect involvement of vanadium haloperoxidases in the production of huge amounts of bromoform and dibromomethane. Some of the global sources are discussed and from the literature a picture emerges in which oxidized brominated species generated by phytoplankton, seaweeds and cyanobacteria react with dissolved organic matter in seawater, resulting in the formation of intermediate brominated compounds. These compounds are unstable and decay via a haloform reaction to form an array of volatile brominated compounds of which bromoform is the major component followed by dibromomethane.
The objective was to determine if supplementing a dairy cow diet with an exogenous fibrolytic enzyme additive (Econase RDE; AB Vista, Marlborough, Wiltshire, UK) altered fermentation, pH, and microbial populations in the rumen or enteric methane (CH(4)) emissions. In a companion study, this enzyme additive improved efficiency of fat-corrected milk production in a dose-dependent manner by up to 11% for early lactation dairy cows. Nine ruminally cannulated, lactating Holstein cows were used in a replicated 3 × 3 Latin square design with 21-d periods. Dietary treatments were 0 (control), 0.5 (low), and 1.0 (high) mL of enzyme/kg of total mixed ration dry matter. Rumen contents were collected on 2 d (d 15 and 19), ruminal pH was measured continuously for 6 d (d 13 to 18) by using an indwelling system, and enteric CH(4) production was measured for 3 d (d 16 to 18) using the sulfur hexafluoride tracer gas technique. The enzyme additive did not alter volatile fatty acids, NH(3), pH, or population densities of total protozoa, bacteria, and methanogens in ruminal fluid. However, population densities of certain bacteria, calculated as copy number of species-specific 16S-rRNA, were affected by enzyme treatment. Population density of Ruminobacter amylophilus was increased and that of Fibrobacter succinogenes tended to be increased by the high enzyme treatment. Selenomonas ruminantium tended to increase linearly with increasing levels of enzyme in the diet, although its population density was only numerically increased by the high enzyme treatment. Streptococcus bovis, however, tended to be decreased by the low enzyme treatment. Increasing the level of enzyme supplement in the diet also linearly increased enteric CH(4) production, even when adjusted for feed intake or milk production (19.3, 20.8, and 21.7 g of CH(4)/kg of dry matter intake or 12.9, 13.6, and 15.1g of CH(4)/kg of milk for the control, low, and high enzyme treatments, respectively). This shift in ruminal bacterial communities and higher CH(4) emissions could imply increased ruminal digestion of feed, which needs to be substantiated in longer term studies.
The effects of the anti-methanogenic compound, bromochloromethane (BCM), on rumen microbial fermentation and ecology were examined in vivo. Japanese goats were fed a diet of 50 % Timothy grass and 50 % concentrate and then sequentially adapted to low, mid and high doses of BCM. The goats were placed into the respiration chambers for analysis of rumen microbial function and methane and H2 production. The levels of methane production were reduced by 5, 71 and 91 %, and H2 production was estimated at 545, 2941 and 3496 mmol/head per d, in response to low, mid and high doses of BCM, respectively, with no effect on maintenance feed intake and digestibility. Real-time PCR quantification of microbial groups showed a significant decrease relative to controls in abundance of methanogens and rumen fungi, whereas there were increases in Prevotella spp. and Fibrobacter succinogenes, a decrease in Ruminococcus albus and R. flavefaciens was unchanged. The numbers of protozoa were also unaffected. Denaturing gradient gel electrophoresis and quantitative PCR analysis revealed that several Prevotella spp. were the bacteria that increased most in response to BCM treatment. It is concluded that the methane-inhibited rumen adapts to high hydrogen levels by shifting fermentation to propionate via Prevotella spp., but the majority of metabolic hydrogen is expelled as H2 gas.
This mini-review summarizes the category, characteristics, and the application fields of the chemical methanogenic inhibitors. Usually, the chemical methanogenic inhibitors can be divided into "specific" and nonspecific inhibitors. The former group includes the structural analogs of coenzyme M and HMG-CoA inhibitors. The nonspecific group includes many chemicals which can inhibit the activity of both methanogens and non-methanogens. The chemical inhibitors of methanogenesis have been widely used in the fields of understanding methane production and consumption in pure culture or in complex natural environment, production of value-added substances, such as volatile fatty acids and hydrogen, and reduction of energy loss and improvement of the efficiency of ruminal energetic transformations. Finally, with an increasing understanding of the mechanistic effects of the chemical inhibitors of methanogenesis, it is possible that some could be used to develop into promising feed additives to reduce losses associated with enteric methane production or as useful tools to screen microbial consortia from various biotechnological applications to enhance hydrogen and acid production.