235 Interactive Effects of Zinc Oxide and Mannan Oligosaccharides on Nursery Swine Performance

Abstract Peer-reviewed data have suggested that Mannan oligosaccharide [Actigen (ACT)] could positively influence gut barrier function and limit pathogenic bacteria adhesion to epithelial cells, thus representing a feasible alternative or a complement to pharmacological concentrations of zinc oxide (ZnO) in nursery swine diets. To scrutinize this hypothesis, a total of 2,592 pigs (initial BW 6.9 ± 0.4 kg) were used in a 37-day trial to determine the interactive effects of ZnO and ACT on nursery pig performance. Pens of 36 mixed sex pigs were randomly assigned to 1 of 6 dietary treatments with 12 replications per treatment. Treatments were arranged in a 2 × 3 factorial arrangement with main effects of zinc (100 or 3,000 ppm) and ACT (0, 400, and 800 ppm). Diets were fed in two phases: phase 1 from d 0 to d 21 and phase 2 from d 22 to d 37, which represented the experimental and common diets, respectively. No significant ZnO × ACT interactions (P > 0.10) were observed in growth performance or dead and removals in this study (Table 1). From d 0 to d 21, pigs fed diets with 3,000 ppm Zn had greater (P < 0.0001) ADFI, greater (P < 0.0001) ADG, and improved (P < 0.0001) feed efficiency compared with pigs fed diets containing 100 ppm Zn. From d 22 to d 37, pigs initially fed diets with 3,000 ppm Zn had reduced (P = 0.009) ADG and poorer (P = 0.0009) G:F, without evidence for differences (P = 0.615) in ADFI, compared with pigs fed diets containing 100 ppm of Zn. Additionally, pigs fed diets containing 3,000 ppm of Zn marginally increased (P = 0.077) removals prevalence compared with pigs fed diets with less Zn concentration. However, pigs fed diets with 3,000 ppm Zn and incremental levels of ACT marginally decreased (linear, P = 0.083) dead and removals prevalence. In conclusion, pigs fed pharmacological ZnO concentration increased overall growth performance, yet it was drastically worsened when Zn was reduced to basal levels, despite ACT supplementation. Additionally, whereas pigs fed the greatest Zn level marginally increased morbidity occurrence, ACT marginally reduced morbidity and mortality.