Identification of bioactives from the red seaweed Asparagopsis taxiformis that promote antimethanogenic activity in vitro

• Published in: Journal of applied phycology Vol. 28; no. 5; pp. 3117 - 3126
• Main Authors: Machado, Lorenna, Magnusson, Marie, Paul, Nicholas A., Kinley, Robert, de Nys, Rocky, Tomkins, Nigel
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.10.2016; Springer Nature B.V
• Subjects: Algae; Asparagopsis; Asparagopsis taxiformis; Bioassays; Biomass; Biomedical and Life Sciences; Bos indicus; dibromoacetic acid; Ecology; Feed supplements; Fermentation; Freshwater & Marine Ecology; hexane; Life Sciences; macroalgae; Methane; methane production; methanol; methylene chloride; Organic matter; Plant Physiology; Plant Sciences; rumen fluids; steers; volatile fatty acids; zebu; Rhodophyta; Seaweed; Methane inhibitors; Red macroalgae; Natural products; Bromoform
• ISSN: 0921-8971; 1573-5176
• DOI: 10.1007/s10811-016-0830-7

Asparagopsis taxiformis has potent antimethanogenic activity as a feed supplement at 2 % of organic matter in in vitro bioassays. This study identified the main bioactive natural products and their effects on fermentation using rumen fluid from Bos indicus steers. Polar through to non-polar extracts (water, methanol, dichloromethane and hexane) were tested. The dichloromethane extract was most active, reducing methane production by 79 %. Bromoform was the most abundant natural product in the biomass of Asparagopsis (1723 μg g −1 dry weight [DW] biomass), followed by dibromochloromethane (15.8 μg g −1 DW), bromochloroacetic acid (9.8 μg g −1 DW) and dibromoacetic acid (0.9 μg g −1 DW). Bromoform and dibromochloromethane had the highest activity with concentrations ≥1 μM inhibiting methane production. However, only bromoform was present in sufficient quantities in the biomass at 2 % organic matter to elicit this effect. Importantly, the degradability of organic matter and volatile fatty acids were not affected at effective concentrations.