Exploration of Methane Mitigation Efficacy Using <i>Asparagopsis</i>-Derived Bioactives Stabilized in Edible Oil Compared to Freeze-Dried <i>Asparagopsis in Vitro</i>

Abstract

Asparagopsis oil products are of interest due to the stabilizing effects of the Asparagopsis-derived antimethanogenic bioactive compound bromoform (CHBr 3 ). 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 CHBr 3 delivery. Relative methane (CH 4 ) emissions (mL/g) are based on in vitro apparent feed digested dry matter (IVDDM) after 24, 48, and 72 h of fermentation. CHBr 3 contained in FD-Asp was included at 95, 191, and 286 mg/kg, and CHBr 3 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 CH 4 emissions, Mid FD-Asp demonstrated 91%, 44%, and 37% reductions, and the High FD-Asp demonstrated complete inhibition of CH 4 , after 24, 48, and 72 h of fermentation, respectively. Comparatively, Low Asp-Oil demonstrated a 46%, 28%, and 18% CH 4 reduction, Mid Asp-Oil resulted in 99%, 92%, and 73% reductions, and the High Asp-Oil demonstrated complete inhibition of CH 4 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 CH 4 mitigating feed supplement but is also able to be delivered in edible oil forms which How to cite this paper:

Shelf-life stability of Asparagopsis bromoform in oil and freeze-dried powder

“…Additionally, the use of a lipid source in feed mixtures is already implemented as an approach for methane mitigation in ruminants making it a practical candidate to deliver bromoform (Beauchemin et al 2007). The effectiveness of bromoform in oil for methane mitigation in vitro has been demonstrated recently by Kinley et al (2022). Animal trials using Asp-Oil are in progress.…”

“…Magnusson et al (2020) has shown that when fresh harvested Asparagopsis is immersed and homogenized into edible oils (Asp-Oil), there is a transfer and stabilization of bromoform. Furthermore, Asp-Oil has been shown to be as effective as FD-Asp at methane mitigation in vitro (Kinley et al 2022). While continuous improvements toward Asparagopsis derived bromoform conservation are being made, it is also important to understand the retention of bromoform within FD-Asp and Asp-Oil which will ultimately be used to identify their respective shelf-life for on farm use.…”