Macroalgae (algae) fed to ruminants-cattle, buffalo, and camelids-can lower their enteric emissions of greenhouse gases (methane, CO4). (1)
Therefore, it is appropriate to further investigate their potential contribution to the sustainable development of animal husbandry, in line with FAO (2019) recommendations. (2)
An excerpt from the scientific review (Beauchemin et al., 2022) devoted to options for mitigating enteric methane emissions from farm animals is proposed. (3)
1) Blue bioeconomy. Algae, agriculture and aquaculture
Blue bioeconomy
is the concept that best expresses research and innovation on the most unexplored treasures of oceans and fresh waters, algae. Macroalgae and microalgae can perform ecosystem functions, from carbon sequestration to water phytodepuration and environmental remediation. In addition to providing high nutritive value biomass with a variety of applications. Human and animal nutrition, medicine and cosmetics, agriculture, biofuels.
The European Commission acknowledged the need to develop this production sector-still marginal in the Old Continent-in its communication ‘Towards a Strong and Sustainable EU Algae Sector‘ (4,5). The 23 actions planned in Brussels, as noted, include:
- starting in 2023, the evaluation of market potential, efficiency and safety of algae-based materials as fertilizers and/or biostimulants (Action 5. See Note 6),
- by the end of 2024, including on the basis of good feed practices and indicators, promote the replacement of fish-based feeds with algae-based feeds (Action No. 7).
2) Algae and animal husbandry
The role of macroalgae and microalgae and florotannins in animal husbandry has already been successfully demonstrated in Italy, thanks to Algatan’s own research and experience, in strengthening the microbiota of animals. To the point of reducing-to the point of eliminating where possible-the use of coccidiostats and antibiotics in poultry farming. (7) A major innovation to mitigate the phenomenon of antibiotic resistance(AMR, Anti-Microbial Resistance).
Important results have also been achieved in pig farming, where it has also been possible to develop ‘antibiotics-free‘ meat lines, as well as on cattle and sheep. (8) However, little attention has so far been paid by institutions and livestock operators to the innovation described above. As well as to the potential of algae to reduce enteric methane emissions from ruminants. Essential among other things also in a logic of carbon farming and carbon credits. (9)
3) Role of algae in reducing methane emissions from ruminants.
Seaweeds have a chemical composition that varies significantly depending on the species, harvest period, and growth environment. The scientific review under review (Beauchemin et al., 2022) reports the studies published so far on some macroalgae that contain bioactive compounds that can inhibit methanogenesis in ruminants. (1)
3.1) Macroalgae examined.
‘Red algae such as Asparagopsis taxiformis and Asparagopsis armata accumulate halogenated compounds, among which bromoform abounds (Machado et al., 2016). Halogenated methane analogs react with vitamin B12 to block the last step of methanogenesis in methanogenic archaea (Wood et al., 1968).
Other algae contain polysaccharides, proteins, peptides, bacteriocins, lipids, florotannins, saponins, and alkaloids. In turn known to reduce methane production by suppressing archaea and protozoa. Causing however. In some cases, an undesirable decrease in nutrient degradability (Abbott et al., 2020)‘. (1)
3.2) In vivo studies
‘In vivo studies. on ewes, steers, and dairy cows have reported dose- and ration-dependent reductions in methane (CH4) production ranging from 9 to 98 percent by supplementing Asparagopsis in the diet (Li et al., 2018; Roque et al., 2019a, 2021; Kinley et al., 2020; Stefenoni et al., 2021).
A substantial reduction in CH4 production for cattle was confirmed in a meta-analysis (Lean et al., 2021). The effectiveness of Asparagopsis for CH4 mitigation depends on its bromoform concentration, which ranges from 3.0 to 51.0 mg/kg DMI (Kinley et al., 2020; Roque et al., 2019a, 2021; Stefenoni et al., 2021)‘. (1)
3.3) Asparagopsis
‘The Asparagopsis may be more effective in reducing CH4 production with high concentrate diets than with high forage diets (Roque et al., 2021). Although there is concern that Asparagopsis may lose efficacy in the long term (Hristov et al., 2022). Studies on the effectiveness of other algae on CH4 production are mostly limited to in vitro conditions (Abbott et al., 2020), although interest is growing.
Dietary supplementation with Asparagopsis reduced feed intake in a dose-dependent manner in most but not all experiments. (…). Asparagopsis supplementation has been reported to increase feed efficiency in some small-scale studies (Kinley et al., 2020; Roque et al., 2021). The inclusion of Asparagopsis in the diet had no effect on carcass quality, meat quality or taste (Kinley et al., 2020; Roque et al., 2021), (…).’ (1)
3.4) Elements of attention
The valuable scientific review (Beauchemin et al., 2022) also points out some items for attention. From a food safety point of view, it is necessary to check for the possible presence of contaminants in seaweed. In addition to concentrations of minerals such as iodine, so that the transfer to animal products (e.g., milk) does not exceed the Acceptable Daily Intakes (ADI) of various consumer groups.
It is also important to ‘Sustainably grow seaweed in aquaculture or marine systems with a constant concentration of active compounds, which must be maintained during transport, handling, storage and animal feeding. (…)
The inclusion of other algae in ruminant diets may be acceptable to consumers if there is no risk of toxicity and if there are no unpleasant flavors in the meat or milk.’ (1)
Interim conclusions
‘Further research is needed in vivo to determine CH4 mitigation and productivity changes under different diet and management conditions for both bromoform-containing and other algae (Lean et al., 2021).
The use of macroalgae as an antimetanogenic strategy may be feasible in confined and mixed systems, but is likely to be difficult to implement in extensive systems.
‘For the integration of animals into extensive systems, it is necessary to design delivery mechanisms that do not reduce the efficacy of the bioactive compounds in macroalgae.’ (1)
Dario Dongo
Cover image from Toki™Asparagopsis taxiformis Feed (Zhejiang, China) https://asparagopsistaxiformisfeed.com/
Notes
(1) Antonio Gattuli. Algae against the greenhouse effect. GIFT (Great Italian Food Trade). 22.5.18
(2) Dario Dongo, Marina De Nobili. Livestock, FAO proposes 5 areas of action to reduce greenhouse gas emissions. GIFT (Great Italian Food Trade). 29.8.20
(3) Karen A. Beauchemin, Emilio M. Ungerfeld, Adibe L. Abdalla, Clementina Alvarez, Claudia Arndt, Philippe Becquet, Chaouki Benchaar, Alexandre Berndt, Rogerio M. Mauricio, Tim A. McAllister, Walter Oyhantçabal, Saheed A. Salami, Laurence Shalloo, Yan Sun, Juan Tricarico, Aimable Uwizeye, Camillo De Camillis, Martial Bernoux, Timothy Robinson, Ermias Kebreab (2022). Invited review: Current enteric methane mitigation options. Journal of Dairy Science, Volume 105, Issue 12, 2022, Pages 9297-9326. ISSN 0022-0302. https://doi.org/10.3168/jds.2022-22091
(4) European Commission Communication to the European Parliament and the Council. Towards a Strong and Sustainable EU Algae Sector. https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=COM:2022:592:FIN COM(2022) 592 final
(5) Marta Strinati. European Commission proposes 23 actions for the seaweed industry. GIFT (Great Italian Food Trade). 23.11.22
(6) Dario Dongo, Andrea Adelmo Della Penna. Biostimulants in olive growing, organic revolution. Scientific Review. GIFT (Great Italian Food Trade). 14.5.21
(7) Dario Dongo, Andrea Adelmo Della Penna. Antibiotic-free poultry farming, the Italian way. GIFT (Great Italian Food Trade). 14.12.20
(8) Dario Dongo, Andrea Adelmo Della Penna. Animal husbandry, algae and microalgae to prevent antibiotic use. Algatan. GIFT (Great Italian Food Trade). 9.9.20
(8) Dario Dongo, Giulia Pietrollini. Carbon farming , Council green light for EU certification of carbon credits in agriculture. GIFT (Great Italian Food Trade). 21.12.22
Dario Dongo, lawyer and journalist, PhD in international food law, founder of WIISE (FARE - GIFT - Food Times) and Égalité.
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