Abstract Essential oils (EO) are bioactive compounds of plant origin. Although inconsistent, improvements in animal performance have been reported with EO supplementation. While the exact mode of action and physiological effects are not fully understood, most are associated with increasing diet palatability, enhancement of endogenous secretions, and antimicrobial effects. To evaluate the effects of a novel essential oil blend (EOB1; Alltech, Nicholasville, KY) on growth performance, removals, and mortality rate of pigs, two experiments were conducted under commercial conditions. In Exp. 1, a total of 2,462 pigs (initially 6.0 kg of BW) were used in a 38-d trial. Pigs were placed in pens with 33 to 34 pigs each and allotted to 1 of 4 dietary treatments with 18 replicates per treatment. Treatments consisted of 1) Negative control (NC), 2) NC + 100 ppm EOB1, 3) NC + 200 ppm EOB1, and 4) NC + 200 ppm of a generic EOB (EOB2). In Exp. 2, a total of 1,008 pigs (initially 6.0 kg of BW) were used in a 43-d trial. Pigs were placed in pens with 28 pigs each and allotted to 1 of 4 dietary treatments with 9 replicates per treatment. Dietary treatments consisted of increasing levels of EOB1 (0, 200, 400, and 600 ppm). In both experiments, pigs were fed a commercial nursery program comprised of two phases formulated to meet or exceed NRC (2012) nutrient requirements. In Exp. 1, from d 0 to 17, pigs fed 100 ppm EOB1 reduced (P 0.050) ADG and ADFI compared to pigs fed the NC, 200 ppm EOB1, or EOB2. A G:F improvement (P = 0.032) was observed for pigs fed EOB2. From d 17 to 38 and overall (d 0 to 38), pigs fed 200 ppm EOB1 or EOB2 improved (P = 0.001) G:F. Numerically, pigs fed 200 ppm EOB1 or EOB2 had the lowest mortality and highest full value pig rates. In Exp. 2, from d 0 to 21, pigs fed increasing levels of EOB1 improved (linear; P 0.05) ADG and G:F, with marginally higher (linear, P = 0.079) ADFI. From d 21 to 43, G:F was improved (linear, P = 0.001). Overall (d 0 to 43), pigs fed increasing levels of EOB1 improved (linear, P = 0.030) ADG, G:F (quadratic; P = 0.004), and final BW (quadratic; P = 0.050). Furthermore, removal rate was marginally lower (linear; P = 0.057) with numerically (linear, P = 0.112) greater full value pigs. Although some outcomes were linear, the largest improvement was observed up to 400 ppm EOB1 supplementation. In summary, the supplementation of EOB1 improved growth performance and health outcomes in nursery pigs raised under commercial conditions.
Soto et al. (Wed,) studied this question.