Impact of orange essential oil on enteric methane emissions of heifers fed bermudagrass hay

Rafael Jiménez-Ocampo; María D Montoya-Flores; Gerardo Pamanes-Carrasco; Esperanza Herrera-Torres; Jacobo Arango; Mirna Estarrón-Espinosa; Carlos F Aguilar-Pérez; Elia E Araiza-Rosales; Maribel Guerrero-Cervantes; Juan C Ku-Vera

doi:10.3389/fvets.2022.863910

Impact of orange essential oil on enteric methane emissions of heifers fed bermudagrass hay

Front Vet Sci. 2022 Aug 16:9:863910. doi: 10.3389/fvets.2022.863910. eCollection 2022.

Affiliations

¹ Laboratory of Climate Change and Livestock Production, Department of Animal Nutrition, Faculty of Veterinary Medicine and Animal Science, University of Yucatan, Mérida, Yucatan, Mexico.
² National Institute of Research in Forestry, Agriculture and Livestock-INIFAP, Experimental Field Valle del Guadiana, Durango, Mexico.
³ National Center for Disciplinary Research in Physiology and Animal Breeding, National Institute for Forestry, Agriculture and Livestock Research-INIFAP, Queretaro, Mexico.
⁴ Institute of Silviculture and Wood Industry, National Council of Science and Technology-Durango State Juarez University, Durango, Mexico.
⁵ National Technology of Mexico, Technological Institute of Valle del Guadiana, Durango, Mexico.
⁶ Tropical Forage Program-International Center for Tropical Agriculture (CIAT), Palmira, Colombia.
⁷ Food Technology Unit, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, Jalisco, Mexico.
⁸ Department of Animal Nutrition, National Council of Science and Technology-Durango State Juarez University, Durango, Mexico.
⁹ Department of Small Ruminant Nutrition, Faculty of Veterinary Medicine and Animal Science, Durango State Juarez University, Durango, Mexico.

Abstract

In this study, the effects of orange essential oil (OEO) on the rumen fermentation, nutrient utilization, and methane (CH₄) emissions of beef heifers fed a diet of bermudagrass (Cynodon dactylon) were examined. In addition, in vitro and in situ experiments were conducted. The in vitro experiment consisted of three treatments: control (CTL, no OEO), OEO1 (0.25% OEO), and OEO2 (0.5% OEO). The forage to concentrate ratio was 70:30 (dry matter [DM] basis) in all treatments. No changes in pH, proportions of volatile fatty acids, and the acetate:propionate ratio were observed (P > 0.05). The addition of 0.25% OEO resulted in a reduction in CH₄ production (mL/g) relative to the control (P < 0.05). In the in situ experiment, 5 g of total mixed ration (CTL, OEO1, and OEO2) were incubated for 6, 12, 24, 48, and 72 h. Potential and effective degradability were not affected by OEO supplementation (P > 0.05). In the in vivo study, six crossbred beef heifers (Bos indicus × Bos taurus), fitted with rumen cannulas, were assigned to three different treatments: no additive (CTL), 0.25% OEO (OEO1), and 0.5% OEO (OEO2) in a replicated 3 × 3 Latin square (21-day periods). Heifers were fed at 2.8% body weight. In vivo CH₄ production was measured in open-circuit respiration chambers. Reductions in gross energy consumption, apparent total tract digestibility, and rumen valerate concentration were observed for OEO2 compared to the control (P < 0.05). Additionally, decreases in CH₄ emissions (g/day; P < 0.05) and CH₄ (MJ gross energy intake/day; P < 0.05) were observed in response to supplementation of 0.5% OEO as compared to the CTL treatment. Thus, supplementation of 0.5% OEO reduced CH₄ emissions (g/day) by 12% without impacting the DM intake of heifers fed bermudagrass hay as a basal ration.

Keywords: cattle; enteric methane; essential oil; feed additive; plant secondary metabolites.