Potential of the Red Macroalga Bonnemaisonia hamifera in Reducing Methane Emissions from Ruminants

Researchers have been exploring seaweeds to reduce methane (CH4) emissions from livestock. This study aimed to investigate the potential of a red macroalga, B. hamifera, as an alternative to mitigate CH4 emissions. B. hamifera, harvested from the west coast of Sweden, was used in an in vitro experiment using a fully automated gas production system. The experiment was a randomized complete block design consisting of a 48 h incubation that included a control (grass silage) and B. hamifera inclusions at 2.5%, 5.0%, and 7.5% of grass silage OM mixed with buffered rumen fluid. Predicted in vivo CH4 production and total gas production were estimated by applying a set of models to the gas production data and in vitro fermentation characteristics were evaluated. The results demonstrated that the inclusion of B. hamifera reduced (p = 0.01) predicted in vivo CH4 and total gas productions, and total gas production linearly decreased (p = 0.03) with inclusion of B. hamifera. The molar proportion of propionate increased (p = 0.03) while isovalerate decreased (p = 0.04) with inclusion of B. hamifera. Chemical analyses revealed that B. hamifera had moderate concentrations of polyphenols. The iodine content was low, and there was no detectable bromoform, suggesting quality advantages over Asparagopsis taxiformis. Additionally, B. hamifera exhibited antioxidant activity similar to Resveratrol. The findings of this study indicated that B. hamifera harvested from temperate waters of Sweden possesses capacity to mitigate CH4 in vitro

Effect of organic grass-clover silage on fiber digestion in dairy cows

There are differences in grass-clover proportions and chemical composition between herbage from primary growth (PG) and regrowth (RG) in grass-clover leys. Mixing silages made from PG and RG may provide a more optimal diet to dairy cows than when fed separately. We tested the hypotheses that increasing dietary proportions of grass-clover silage made from RG compared with PG would increase digestion rate of potentially degradable NDF (pdNDF), and increase ruminal accumulation of indigestible NDF (iNDF). Eight rumen cannulated Norwegian Red cows were used in two replicated 4×4 Latin squares with 21-day periods. Silages were prepared from PG and RG of an organically cultivated ley, where PG and RG silages were fed ad libitum in treatments with RG replacing PG in ratios of 0, 0.33, 0.67 and 1 on dry matter basis in addition to 8 kg concentrate. We evaluated the effect of the four diets with emphasis on rumen- and total tract fiber digestibility. Increasing RG proportions decreased silage intake by 7%. Omasal flow of pdNDF decreased, whereas iNDF flow increased with increasing RG proportions. Increasing RG proportions decreased rumen pool sizes of NDF and pdNDF, whereas pool sizes of iNDF and CP increased. Increasing RG proportions increased digestion rate of NDF, which resulted in greater total tract digestion of NDF. Pure PG diet had the highest calculated energy intake, but the improved rumen digestion of NDF by cows offered 0.33 and 0.67 of RG leveled out milk fat and protein yields among the three PG containing diets

Sustainability aspects of milk production in Sweden

Resource use efficiency and economic initiatives point towards using less human-edible input in ruminant food production. This could also promote the nutrient-rich dairy products to consumers in comparison with alternative plant-based drinks. The global population is growing and food production will need to increase to feed more people in the future. The Swedish government has launched a national food strategy, which aims to move Swedish food production towards self-sufficiency and sustainability, and greater exports. Simultaneously, strong economic development has stimulated consumers to request more high-value foods, such as meat and refined dairy products. At the same time, public opinion states that today's food production from ruminants is negative for the environment and contributes to climate change. This review assesses some aspects of dietary ingredient composition and feeding choices that can contribute to making Swedish dairy production more sustainable. Efficient dietary methane mitigating strategies can decrease emissions of greenhouse gases in line with European Union targets and avoid major changes in dietary consumption patterns of meat and milk from ruminants. Although feeding management seems to be the most important approach to decrease nitrogen losses, rational use of fertilizers and improved manure management practices on dairy farms should also be considered to decrease the impact of nitrogen losses to the environment

Effect of a Low-Methane Diet on Performance and Microbiome in Lactating Dairy Cows Accounting for Individual Pre-Trial Methane Emissions

Simple Summary Low methane-emitting dietary ingredients have been identified in extensive research conducted during the past decade. This study investigated the effects of replacing grass silage with maize silage, with or without rapeseed oil supplementation, on the methane emissions and performance of dairy cows. Pre-trial measurements of methane-emissions were used in the evaluation. Partial replacement of grass silage with maize silage did not affect methane emissions but reduced dairy cow performance. Adding rapeseed oil to the diet substantially reduced methane emissions due to modified rumen microbiota, resulting in impaired nutrient intake, digestibility, and yield of energy-corrected milk. Correcting for individual cow characteristics of methane emissions did not affect the magnitude of suppression of methane emissions by dietary treatments. This study examined the effects of partly replacing grass silage (GS) with maize silage (MS), with or without rapeseed oil (RSO) supplementation, on methane (CH4) emissions, production performance, and rumen microbiome in the diets of lactating dairy cows. The effect of individual pre-trial CH4-emitting characteristics on dietary emissions mitigation was also examined. Twenty Nordic Red cows at 71 +/- 37.2 (mean +/- SD) days in milk were assigned to a replicated 4 x 4 Latin square design with four dietary treatments (GS, GS supplemented with RSO, GS plus MS, GS plus MS supplemented with RSO) applied in a 2 x 2 factorial arrangement. Partial replacement of GS with MS decreased the intake of dry matter (DM) and nutrients, milk production, yield of milk components, and general nutrient digestibility. Supplementation with RSO decreased the intake of DM and nutrients, energy-corrected milk yield, composition and yield of milk fat and protein, and general digestibility of nutrients, except for crude protein. Individual cow pre-trial measurements of CH4-emitting characteristics had a significant influence on gas emissions but did not alter the magnitude of CH4 emissions. Dietary RSO decreased daily CH4, yield, and intensity. It also increased the relative abundance of rumen Methanosphaera and Succinivibrionaceae and decreased that of Bifidobacteriaceae. There were no effects of dietary MS on CH4 emissions in this study, but supplementation with 41 g RSO/kg of DM reduced daily CH4 emissions from lactating dairy cows by 22.5%

Characterization and in vitro assessment of seaweed bioactives with potential to reduce methane production

This study collates compositional analysis of seaweeds data with information generated from in vitro gas production assays in the presence and absence of seaweeds. The aim was to assess and rank 27 native northern European seaweeds as potential feed ingredients for use to reduce methane emissions from ruminants. It provides information for use in future in vivo dietary trials concerning feed manipulation strategies to reduce CH4 emissions efficiently from domestic ruminants based on dietary seaweed supplementation. The seaweeds H. siliquosa and A. nodosum belonging to phylum Phaeophyta displayed the highest concentration of phlorotannins and antioxidant activity among the macroalgae giving anti-methanogenic effect in vitro, while this explanation was not valid for the observed reduction in methane when supplementing with C. filum and L. digitata in this study. D. carnosa and C. tenuicorne belonging to phylum Rhodophyta had the highest protein content among the macroalgae that reduced methane production in vitro. There were no obvious explanation from the compositional analysis conducted in this study to the reduced methane production in vitro when supplementing with U. lactuca belonging to phylum Chlorophyta. The strongest and most complete methane inhibition in vitro was observed when supplementing with Asparagopsis taxiformis that was used as a positive control in this study

Reducing methane production from stored feces of dairy cows by Asparagopsis taxiformis

The objective was to evaluate whether methane (CH4) production from stored feces of cows previously supplemented with Asparagopsis taxiformis (AT) in their diet was lower compared with the feces of cows not supplemented with AT. We also investigated the possibility of further reducing CH4 production by adding AT to the stored feces of cows. Fecal samples were provided from a feeding trial (during two different periods) of four cows divided into two different groups. One group was supplemented with AT at a level of 0.5% of the total organic matter intake, and the other group was not supplemented with AT. A 2 × 2 factorial design was set in the laboratory for the incubation of feces. Fecal samples from the two groups of cows were divided into two subsamples receiving either no addition of AT or the addition of AT at a level of 0.5% of OM incubated. This resulted in four treatments with two replicates per period. The same design was repeated during period two. In total, 400 g of fresh fecal samples were incubated in 1 L serum bottles for 9 weeks at 39°C in a water bath. CH4 and total gas production were measured on days 1, 4, and 7 and subsequently every 2nd week until the end of the incubation period. Enteric CH4 production showed a significant reduction (61%) when AT was supplemented in the diet of dairy cows. We found that CH4 production from the feces of dairy cows supplemented with AT in their diet was only numerically lower (P = 0.61). Adding AT to the feces of dairy cows significantly reduced CH4 production from the feces by 44% compared with feces without AT. There were no differences observed in the bacterial and archaeal community profiles of fecal samples between cows fed AT and those not fed AT. This study concludes that the addition of AT to stored feces can effectively reduce CH4 production from the feces of dairy cows

Effect of grassland cutting frequency, species mixture, wilting and fermentation pattern of grass silages on in vitro methane yield

Mitigating enteric methane (CH4) emissions is crucial as ruminants account for 5% of global greenhouse gas emissions. We hypothesised that less frequent harvesting, use of crops with lower WSC concentration, ensiling at low crop dry matter (DM) and extensive lactic acid fermentation would reduce in vitro CH4 production. Timothy (T), timothy + red clover mixture (T + RC) or perennial ryegrass (RG), cut either two or three times per season, was wilted to 22.5% or 37.5% DM and ensiled with or without formic acid-based additive. Silages were analysed for chemical composition and fermentation products. In vitro CH4 production was measured using an automated gas in vitro system. Methane production was, on average, 2.8 mL/g OM lower in the two-cut system than in the three-cut system (P < 0.001), and 1.9 mL/g OM lower in T than in RG (P < 0.001). Silage DM did not affect CH4 production (P = 0.235), but formic acid increased CH4 production by 1.2 mL/g OM compared to the untreated silage (P = 0.003). In conclusion, less frequent harvesting and extensive silage fermentation reduce in vitro CH4 production, while RG in comparison to T resulted in higher production of CH4.Effect of grassland cutting frequency, species mixture, wilting and fermentation pattern of grass silages on in vitro methane yieldpublishedVersio

In vitro evaluation of agro-industrial by-products replacing barley in diets to dairy cows

A rapidly growing world population will demand a secure and increased global food supply in the future. Ruminant animals can utilize fibrous plant material not edible to humans efficiently and convert it into highly nutritious food for human consumption. A large number of by-products from the agricultural industry can thereby be suitable feed ingredients in diets to dairy cows. However, the use of agro-industrial by-products in feed rations to dairy cows have to be complementary to basal feed ingredients/efficient in terms of nutrient utilization and not lower production. Several in vitro techniques have been developed to enable rapid and cost-effective evaluation of feed resources as alternative to experiments with live animals. Recently, there has been great progress in the development of the automated gas in vitro technique, which enables comparison of treatment effects on diet digestibility, ruminal fermentation, digestion rate (kd; Huhtanen et al., 2008) and CH4 production (Ramin and Huhtanen, 2012). The aim of this study was to evaluate the effects of replacement of barley by some common agro-industrial by-products in diets based on grass silage on true organic matter digestibility (TOMD), volatile fatty acids (VFA) concentrations, diet kd and CH4 production in vitro

Effects on rumen microbiome and milk quality of dairy cows supplemented the macroalga Asparagopsis taxiformis in a grass silage-based diet

The objective was to determine the effects on rumen microbiome and milk quality of reducing the methane (CH4) produced from enteric fermentation by the addition of Asparagopsis taxiformis (AT) to the diets of dairy cows. Six Nordic Red cows at 122 ± 13.7 (mean ± SD) days in milk, of parity 2.7 ± 0.52 and producing 36 kg ± 2.5 kg milk per day at the start of the trial were divided into three blocks by milk yield and assigned to an extra-period Latin-square change-over design comprising two dietary treatments. An extra period of observation was added to the Latin-square change-over design to control for carry-over effects. The dietary treatments were a diet consisting of grass silage and a commercial concentrate mixture (60:40) either not supplemented or supplemented with 0.5% AT on an organic matter intake basis. On average, daily CH4 production, CH4 yield, and CH4 intensity decreased by 60%, 54%, and 58%, respectively, in cows fed the diet supplemented with AT. Furthermore, hydrogen gas emitted by cows fed diets supplemented with AT increased by more than five times compared with cows fed a non-AT-supplemented diet. Feed intake was decreased and milk production altered, reflecting a decreased yield of milk fat in cows fed an AT-supplemented diet, but feed efficiency increased. Rumen fermentation parameters were changed to promote propionate rather than acetate and butyrate fermentation. The most prominent change in milk quality was an increase in bromine and iodine when the diet was supplemented with AT. The reduction in CH4 was associated with a shift from Methanobrevibacter to Methanomethylophilaceae in the archaeal population and a lower relative abundance of Prevotella in the bacterial population. Changes in milk fat odd-numbered and branched-chain fatty acids in the current study of AT supplementation support observed differences in ruminal archaeal and bacterial populations