Effects of essential oil combinations on sheep ruminal fermentation and digestibility of a diet with fumarate included

Abstract

a b s t r a c tFour Hu sheep (27.5 ± 2.6 kg body weight), fitted with ruminal and duodenal fistula, were used to investigate the effects of a mixture of essential oils (EO) or their active components on rumen fermentation, microbial population, and nutrient digestibility. Four treatments in 4 × 4 Latin square design were used: basal diet added with 25 g/day monosodium fumarate (Control); Control plus 1 g/day of EO combinations (EOC, mixture of equal ratio of oil from clove, oregano, cinnamon, and lemon); and Control plus 0.5 or 1.0 g/day EO active component combinations (EOAC, mixture of eugenol, carvacrol, citral and cinnamaldehyde in equal ratio). The EOC and EOAC treatments were absorbed into microporous starch, and the complex was encapsulated with sodium alginate before use. Each treatment period lasted for 21 days, including 12 days for adaptation. Rumen samples were taken to determine volatile fatty acid (VFA) content and microbial flora. Microbial populations were measured using real-time PCR. The apparent digestibility of nutrients in the total tracts or at different tract parts was measured through total collection method or indicator method, respectively. Rumen pH did not change with the addition of EOC or EOAC. Ammonia nitrogen concentration decreased after addition of either EOC or EOAC. Total VFA content decreased with the addition of EOC or high level of EOAC, with little change under low dose of EOAC. Propionate increased (P<0.05) in animals treated with EOAC or 0.5 g EOAC compared with the control. The ratio of acetate to propionate decreased (P<0.05) with the addition of EOC or EOAC. Protozoan population decreased (P<0.05) with the addition EOC and EOAC, with lower population in the EOAC-treated animals than in the EOC-treated group. The growth of methanogens, Fibrobacter succinogenes, and Butyrivibrio fibrisolvens (P<0.05) was inhibited by addition of EOAC, but not by EOC. Population of fungi and Ruminococcus flavefaciens did not change with the addition of EOC or EOAC. Addition of EOC and EOAC did not influence the feed intake and digestibility of the nutrients in total or at different parts of the digestive tract, but decreased ruminal protein digestibility. Addition of EOC and EOAC Abbreviations: ADFom, acid detergent fiber exclusive residual ash; CP, crude protein; DM, dry matter; DMI, DM intake; EO, essential oils; EOC, essential oils combination; EOAC, essential oils active compounds combination; NDFom, neutral detergent fiber exclusive residual ash; OM, organic matter.

Evaluation of the Effects of Mitigation on Methane and Ammonia Production by Using Origanum vulgare L. and Rosmarinus officinalis L. Essential Oils on in Vitro Rumen Fermentation Systems

“…Similar results were reported by Castillejos et al [43]. Instead, Patra and Yu [30] found that VFA concentration was affected only by oregano and clove EOs while the supplementation of EOs in sheep diets did not show any effect on VFA production [20,36]. Some researchers showed that some EOs have positive effects on VFA molar proportions by decreasing the acetate production and increasing propionate production [44][45][46].…”

“…In vitro NH3 concentration was also decreased by a combination of EOs composed of thyme, oregano, cinnamon and lemon applied at 0-0.5 g/L levels along with fumarate [35]. Lin et al [36] observed a NH3 inhibition with a mixture of EOs composed of clove, oregano, cinnamon and lemon in sheep (1 g/day). Contrasting results on in vivo NH3 production were found by Hristov et al [31] and Tekippe et al [32] by feeding dairy cows with a supplementation of oregano leaves.…”

Impact of Essential Oils Blend on Methane Emission, Rumen Fermentation Characteristics and Nutrient Digestibility in Barki Sheep

“…In vivo studies have been conducted to investigate the effect of EO on feed intake and ruminal and nutrient apparent digestibility, but results are inconsistent (Lin et al, 2013). Santos et al (2010) observed that supplementation of EO complex (eugenol, geranyl acetate and coriander oil) numerically reduced DMI in lactating dairy cow, which agrees with our result on sheep.…”

“…Furthermore, if combining different EO components together can replace natural EOs as additive, existing problems on natural EO such as composition instability, difficulties in collection, and high cost, can be solved. Contrary to our finding regarded methane emission, Lin et al (2012Lin et al ( , 2013 found that a balanced combination of EO and EO active components (a mixture of thyme, oregano, cinnamon, and lemon essential oil at an equal ratio, and a mixture of eugenol, carvacrol, citral, and cinnamylaldehyde at an equal ratio) has greater methane reduction ability compared with other combinations. However, that EO are strong inhibitors of methanogenesis in the rumen could be attributed to different types and concentrations of secondary plant metabolites such as terpeniods and phenylpropanoids present in oils (Agarwal et al, 2009;Sallam et al, , 2012Soltan et al, 2011).…”

“…The results showed decreases or unchanged dry matter intake as well as whole tract digestibility (Benchaar et al, 2006Santos et al, 2010;Lin et al, 2013). Therefore, we hypothesized that a new blend combining EO by equal proportions will be more beneficial on rumen fermentation characteristics and nutrients utilization.…”