The Potential Role of Seaweeds in the Natural Manipulation of Rumen Fermentation and Methane Production

Abstract

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.

Can Seaweed Farming Play a Role in Climate Change Mitigation and Adaptation?

“…Seaweed aquaculture generates food while minimizing the impacts associated with land-based food production systems (e.g., Duarte et al, 2009). For instance, recent in vitro experiments showed that fermentation of seaweed, simulating that of ruminant digestion, substantially reduced methane emissions Maia et al, 2016), and that addition of only 2% of specific seaweed species to the diet of cattle could reduce the methane emission from cattle production by 99% . Indeed, ruminants were traditionally fed seaweed in many coastal regions during periods of feed scarcity, but the potential benefits in terms of reduced methane emissions have only recently been realized Maia et al, 2016).…”

“…For instance, recent in vitro experiments showed that fermentation of seaweed, simulating that of ruminant digestion, substantially reduced methane emissions Maia et al, 2016), and that addition of only 2% of specific seaweed species to the diet of cattle could reduce the methane emission from cattle production by 99% . Indeed, ruminants were traditionally fed seaweed in many coastal regions during periods of feed scarcity, but the potential benefits in terms of reduced methane emissions have only recently been realized Maia et al, 2016). Hence, supplementing feed for ruminant cattle with seaweed holds a potential to reduce methane emissions, a possibility that, if confirmed by in vivo and farm-scale experiments, could greatly contribute to mitigate emissions of this powerful greenhouse gas.…”

Rumen fermentation of lignocellulosic biomass from wheat straw and date leaf inoculated with bacteria isolated from termite gut

“…Cows were housed at the Agricultural Campus of Abel Salazar Biomedical Sciences Institute, University of Porto (ICBAS-UP, Vairão, Vila do Conde, Portugal) and were handled in strict accordance with good animal practice (European Union Directive 2010/63/EU). Experimental animal procedures were previously approved, licensed and conducted by trained scientists, as described by Maia et al (2016).…”

“…For determination of volatile fatty acids (VFA), 1.0 ml of supernatant was added to 0.25 ml 25% orthophosphoric acid solution with 16 mM 3-methyl-valeric acid (internal standard; Sigma-Aldrich Inc., St. Louis, MO, USA) and stored at −20 °C. Ammonia nitrogen was determined by steam distillation and VFA by gas liquid chromatography as described by Maia et al (2016). Fermentation residues were oven-dried at 60 °C for 48 h for estimation of DM disappearance (DMD).…”

Considering land–sea interactions and trade‐offs for food and biodiversity

“…Agriculture is the greatest contributor to non-CO 2 emissions globally (Smith et al, 2014); methane produced by cattle rumination is the single greatest source (Sonesson et al, 2010). Although, novel feed ingredients, such as seaweed, show promise for reducing methane production (Maia, Fonseca, Oliveira, Mendonc ßa, & Cabrita, 2016). Outside of the production cycle, land clearing is also responsible for huge releases of CO 2 and contributes to warming via alterations to the albedo of the Earth's surface (Myhre et al, 2013;Smith et al, 2014).…”