The potential role of two red seaweeds that promote anti-methanogenic activity and rumen fermentation profiles under laboratory conditions

Authors: Min, Byeng Ryel; GENOVESE, GIUSI - University Of Messina; Castleberry, Bobbie - Lana; Lockard, Catherine; Waldrip, Heidi; Parker, David; Miller, Daniel; AKBAY, ALEXIA - Symbrosia Inc; MORABITO, MARINE - University Of Messina; MANGHISI, ANTONIO - University Of Messina; SPAGNUOLO, DAMIANO - University Of Messina; Brauer, David

Submitted to: American Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 4/27/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary: The livestock industry contributes 14.5 to 19% of global greenhouse gas (GHG) emissions and accounts for approximately 11% of the GHG emissions in the U.S. The ability of a CH4 inhibitor to increase metabolizable energy in the ruminant diet and effectively reduce enteric CH4 emissions, is therefore an area of interest. There is a growing interest in the use of seaweed as the alternative natural feed additives to mitigate methane production. However, the effects of two different red seaweeds (Asparagopsis taxiformis vs. A. armata) supplementation on in vitro gas production, in vitro dry matter digestibility (IVDMD) and rumen fermentation profiles in cattle diets are not fully defined. Therefore, scientists from USDA-ARS at Bushland, TX, University of Messina, Italy, and Symbrosia Inc, HI, analyzed the effects of dietary two red seaweeds on in vitro methane gas production, IVDMD, and rumen fermentation profiles. Supplementation with two red seaweeds induced changes in rumen fermentation characteristics, reduced methane emissions, and increased feed efficiency as measured by acetate/propionate ratio. These data indicate that red seaweeds supplementation may benefit beef and dairy cattle by decreasing the GHG emissions and increasing animal feed efficiency by changing rumen fermentation.

Technical Abstract: Ruminal methane (CH4) production results from carbohydrate fermentation by ruminal microbiota (methanogens) to produce CH4, volatile fatty acids (VFA), carbon dioxide (CO2), nitrous oxide (N2O), and hydrogen (H2) in a reduction pathway. The aims of this study were to assess the effects of two red seaweed (RSW) species (Asparagopsis taxiformis and A. armata; collected from Messina, Italy). The two RSW were identified by DNA barcoding and genetic data were deposited in BOLD Systems (REAPP006-21, REAPP004-21, respectively). The two RSW were used at dietary inclusion levels (0, 2, and 4% as-fed basis) in an anaerobic in vitro study (39°C for 48-h) to examine greenhouse gas (GHG) production and VFA profiles. Gases were collected using an ANKOM Gas Production system and analyzed for CH4 and N2O by gas chromatography. Asparagopsis taxiformis contained higher levels of bromoform (201 vs. 7.0 mg/kg DM), iodine (4820 vs. 3260 ppm), and crude protein (16 vs. 15.6% DM), than A. armata, which contained higher levels of acid detergent fiber (ADF; 7.7 vs. 19.0%) and neutral detergent fiber (NDF; 13.2 vs. 19.2%), respectively. RSW supplementation increased total gas, butyrate and valerate production (P < 0.01), while production of CH4 (mg/g DM), acetate (A), propionate (P), A/P ratios and in vitro dry matter digestibility (IVDMD; % DM) were reduced (P < 0.01) as RSW supplementation increased. In the presence of A. taxiformis, production of N2O (µg/g DM), tended to be less (P = 0.1) at 2% DM, but increased (P < 0.01) N2O production with A. armata at the 2 and 4% DM. Therefore, it may be possible to suppress methanogenesis both directly and indirectly by addition of RSW. To efficiently use seaweeds as feed ingredients with nutritional and environmental benefits, more research is required to determine the mechanisms underlying seaweed and dietary substrate interactions.