TITLE:
Productivity of Commercial Feedlot Beef Production Significantly Improved by Asparagopsis Bioactives Stabilized in Canola Oil
AUTHORS:
Robert D. Kinley, Breanna M. Roque, Sigrid L. Mackenzie, Marina R. S. Fortes, Chiara Palmieri, Garth Tarr, Holly Cuthbertson, Rodney Polkinghorne, Frances C. Cowley
KEYWORDS:
Asparagopsis, Bromoform, Enteric Methane, Feed Efficiency, Ruminant, Seaweed
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.15 No.10,
October
21,
2024
ABSTRACT: Research using open-circuit respiration chambers has established that Asparagopsis bioactive compounds stabilized in canola oil (Asp-Oil), delivering a range of inclusion between 34 - 51 mg bromoform (CHBr3)/kg dry matter intake (DMI), inhibits methane (CH4) emissions > 98% in feedlot cattle. In this study, Asp-Oil was fed at 35 mg CHBr3/kg DMI in the feedlot finisher diet under highly replicated and commercially relevant conditions, and adequately powered to confirm differences as low as 3.3% in feed conversion efficiency (FCE). The study also evaluated the effect of Asp-Oil on CH4 production (g/day), carcass and meat-eating qualities, animal health, and food safety. The experiment consisted of 300 Angus-Shorthorn (Bos taurus) steers in 30 pens of 10 and fed a barley-based ration supplemented with canola oil (Control, n = 15), or Asp-Oil (n = 15) for total 81-d, inclusive of 21-d transition to full Asp-Oil and grain inclusion in the finisher ration. Reduction of CH4 was measured using GreenFeed Emissions Monitors (GEM) in a subset of 2 pens in both Control and Asp-Oil. However, 67% of CH4 measurements were recorded below the GEM’s limit of detection. An inhibition range of 58% - 98% was demonstrated by collectively using GEM and preliminary respiration chamber measurements. Asp-Oil improved FCE 7.4% in the finisher diet, and 5.6% across transition and finisher periods. During the transition steps the steers had not yet received their full allocations of grain and Asp-Oil which is responsible for the lower FCE benefits. A 4.1% lower DMI in the finisher period contributed to benefits in FCE with no effect on daily weight gains. Cost of feed and weight gain were reduced $0.35/head/day and $0.23/kg, respectively, in steers receiving Asp-Oil. Residues of Asparagopsis CHBr3 were not detected in any sample and only trace iodide and bromide were detected in livers and kidneys of both Control and Asp-Oil steers at levels safe for human consumption. Steers demonstrated normal rumen development typical of feedlot diets. This study confirms that Asp-Oil safely induces significant productivity benefits and CH4 reductions in feedlot beef production. Commercial adoption of Asparagopsis can benefit feedlot beef production and reduces the climate change contribution of livestock production.