Synergistic Effects of Essential Oil Blends and Fumaric Acid on Ruminal Fermentation, Volatile Fatty Acid Production and Greenhouse Gas Emissions Using the Rumen Simulation Technique (RUSITEC)

Abstract

This study investigated the combined impact of essential oil blends (EOBs) and fumaric acid (FA) on ruminal fermentation in dairy cows using the rumen simulation technique (RUSITEC) system. Three rumen-cannulated, non-lactating Holstein Friesian cows served as inoculum donors. The substrate, a total mixed ration (TMR), comprised corn silage, alfalfa hay, and a concentrate mix in a 3:1:1 ratio. The four treatments evaluated were Control (TMR without additives), EFA1 (TMR + EOB1 + FA), EFA2 (TMR + EOB2 + FA), and EFA3 (TMR + EOB3 + FA). Sixteen fermentation chambers were randomly assigned to the treatments, each with four replicates, following a completely randomized design during a 9-day experimental period. EOBs and FA were added at 10 µL/g feed and 3% of TMR, respectively. After a 4-day adaptation, samples were collected for 5 days. Results revealed that EFA1 significantly reduced (p = 0.0351) CH4 emissions by 60.2% without negatively impacting dry matter disappearance, fiber fraction digestibility, pH, or gas volume. All EFAs increased (p < 0.001) the propionate molar proportion and decreased (p < 0.001) the acetate-to-propionate ratio. EFA2 decreased (p < 0.05) the acetate proportion by 3.3% compared to the control. In conclusion, EFA1 is recommended as an effective nutritional intervention to mitigate CH4 emissions and optimize ruminal fermentation in dairy cows.

A Mixture of Prebiotics, Essential Oil Blends, and Onion Peel Did Not Affect Greenhouse Gas Emissions or Nutrient Degradability, but Altered Volatile Fatty Acids Production in Dairy Cows Using Rumen Simulation Technique (RUSITEC)

“…In the present study, the addition of GEO, MEO, and OLEO had no significant effect on CH 4 , CO 2 , NH 3 , and H 2 S production. This contradicts a previous study from our lab in which a combination of EOB containing garlic, lemongrass, cumin, lavender, and nutmeg and fumaric acid significantly reduced CH 4 gas emissions by 60% [26]. This could be attributed to the low dosage of EOB (3 µL/g) used in this present study, which is much lower (3 µL/g in the present experiment vs. 10 µL/g in the previous one) than that used in the previous study [26].…”

“…Monitoring gas production can provide insights into the dynamics of ruminal fermentation and the potential impacts of dietary interventions or feed additives. The lack of significant changes in gas production and effluent volume, in the present study, suggests that these interventions are safe for use in ruminant diets without causing adverse effects on rumen fermentation [26]. This observation is consistent with a previous study from our lab in which EOB and fumaric acid inclusion in the diets of dairy cows had no adverse effects on gas production [26].…”

“…The RUSITEC system used in the present study had two identical 8-chamber (n = 16 fermenters) units, and the general incubation procedure was as described in Alabi et al [26]. The fermentation vessels had a 1000 mL capacity, with an inlet for buffer infusion and an effluent output port.…”

“…A DM3 gas flowmeter (Alexander Wright Ltd., London, UK) was used to estimate volume and expressed in mL/d. The GHG concentrations, including CH 4 , CO 2 , ammonia (NH 3 ), and H 2 S, were estimated from the effluent flasks using a portable Biogas 5000 analyzer (Landtec, Dexter, MI, USA) as described in Alabi et al [26].…”

Effects of Different Essential Oil Blends and Fumaric Acid on In Vitro Fermentation, Greenhouse Gases, Nutrient Degradability, and Total and Molar Proportions of Volatile Fatty Acid Production in a Total Mixed Ration for Dairy Cattle

“…Alternative products to conventional antibiotics, which serve as growth promoters in animal husbandry, have been investigated over the last two decades [6][7][8]. Studies have shown that various plant extracts, individual or essential oil blends (EOBs), probiotics, prebiotics, and algae rich in biologically active components can modify rumen fermentation, leading to decreases in the production of CH 4 and ammonia nitrogen in the rumen with mixed results [6,9,10]. The U.S. FDA has categorized some of these extracts as generally recognized as safe for human consumption [5,11].…”