DOI: 10.1111/asj.70225 ISSN: 1344-3941
The Potential Role of Two Red Macroalgae (
Asparagopsis taxiformis
and
A. armata
) That Promote Anti‐Methanogenic Activities in Laboratory Conditions
Byeng R. Min, Giuseppa Genovese, Damiano Spagnuolo, Mariline Hilaire, Hossam Ismael, Santosh Chaudhary, Dipti W. Pitta, Nagaraju Indugu ABSTRACT
The objectives of this study were to evaluate the effects of two red macroalgae species (RMS;
Asparagopsis taxiformis
and
A. armata
) on rumen fermentation profiles, greenhouse gas (GHG) emissions, microbiome changes, and anti‐methanogenic activities. The two RMSs were included at dietary levels of 0%, 2%, and 4% (as‐fed basis) in an in vitro experiment with triplicate incubations (
n
= 3). Gases were collected using an ANKOM Gas Production system and analyzed for methane (CH
4
) and nitrous oxide (N
2
O) via gas chromatography. The RMS supplementation increased total gas, lactate, butyrate, valerate, hexanoate, heptanoate, 4‐ethylphenol production, and AGR (non‐glucogenic [acetate + butyrate]/glucogenic [propionate]) ratio (
p
< 0.01), while reducing production of CH
4
(mg/g DM), acetate, propionate, iso‐butyrate, phenylpropionate, phenylacetate, and acetate/propionate (A/P) ratios (
p
< 0.01), and in vitro dry matter digestibility (IVDMD; % DM) (
p
< 0.01) as RMS supplementation increased. With both algal species present, there were decreases in Actinobacteria, Firmicutes (
p
< 0.001), Firmicutes/Bacteroidetes ratio (F/B), and
Methanobrevibacter
sp. (
p
< 0.01), but increases in Spirochetes, Proteobacteria (methanotrophs;
p
< 0.001),
Candidatus methanomethylophilus alvus
(CMC), and non‐methanogenic archaea
Thermoplasma
sp. (
p
< 0.001) at 2% and 4% DM. Therefore, it may be possible to suppress methanogenesis both directly and indirectly by adding RMS.