TITLE:
Exploration of Methane Mitigation Efficacy Using Asparagopsis-Derived Bioactives Stabilized in Edible Oil Compared to Freeze-Dried Asparagopsis in Vitro
AUTHORS:
Robert D. Kinley, Siong Tan, Jemima Turnbull, Shane Askew, Jessica Harris, Breanna M. Roque
KEYWORDS:
Asparagopsis, Edible Oil, Methane, Greenhouse Gas Mitigation, In Vitro
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.13 No.7,
July
25,
2022
ABSTRACT: Asparagopsis oil
products are of interest due to the stabilizing effects of the Asparagopsis-derived antimethanogenic bioactive compound bromoform
(CHBr3). The objective of this in vitro series is to
characterize antimethanogenic efficacy of
freeze-dried Asparagopsis (FD-Asp) and Asparagopsis oil
(Asp-Oil) and compare relative antimethanogenic response over time at multiple
levels of CHBr3 delivery. Relative methane (CH4)
emissions (mL/g) are based on in vitro apparent feed digested dry matter
(IVDDM) after 24, 48, and 72 h of fermentation. CHBr3 contained in
FD-Asp was included at 95, 191, and 286 mg/kg, and CHBr3 contained
in Asp-Oil was included at 78, 117, and 175
mg/kg, to produce the Low, Mid, and High inclusions, respectively. Low FD-Asp
had no significant impact on CH4 emissions, Mid FD-Asp demonstrated
91%, 44%, and 37% reductions, and the High FD-Asp demonstrated complete
inhibition of CH4, after 24, 48, and 72 h of fermentation,
respectively. Comparatively, Low Asp-Oil demonstrated a 46%, 28%, and 18% CH4 reduction, Mid Asp-Oil resulted in 99%, 92%, and 73% reductions, and the High
Asp-Oil demonstrated complete inhibition of CH4 after 24, 48, and 72 h of fermentation, respectively. IVDDM and total
volatile fatty acid (tVFA) production were not changed by the inclusion of FD-Asp and Asp-Oil. The
results from this study show that Asparagopsis is not only a compelling
CH4 mitigating feed supplement
but is also able to be delivered in edible oil forms which will strengthen its
applicability to on-farm use. This study is promising for the utility of
Asp-Oil, and in vivo trials are essential to demonstrate the extent of
efficacy of Asp-Oil in ruminant animals because FD-Asp has consistently
demonstrated greater antimethanogenic efficacy in vivo compared to in
vitro.