115 Effects of a Chronic Lipopolysaccharide Challenge on Growth Performance and Immune Response of Nursery Pigs Fed Differing Sources of Dietary Zinc

Abstract

Abstract Two experiments were conducted to determine the effects of zinc source on growth performance and immune response during a chronic lipopolysaccharide (LPS) challenge. Each study utilized 180 pigs (5.2 kg, 18-21 d) in a 42-d experiment. Pigs were allocated to pens (10 pigs/pen; 5 pens/trt) and pens were randomly assigned to 4 treatments on d 0. Three dietary treatments consisted of the addition of 100 ppm of added zinc from 3 sources (ZnHydroxyCl, ZnSO4, and ZnO). On d 29, 31, 33 and 35 of the study, challenged pigs were injected intramuscularly with LPS (10 ug/kg BW). Additionally, a control group was fed ZnHydroxyCl without receiving LPS. Pigs and feeders were weighed to determine ADG, ADFI, and G:F. Blood samples, BW, and rectal temperature (RT) were taken before the first LPS injection and 3 h post-injection on d 36. Data were analyzed using the MIXED procedure in SAS with pen as the experimental unit. There were no experiment by treatment interactions (P > 0.10). Prior to LPS challenge (d 0–28), there were no effects (P > 0.10) of treatment on ADG, ADFI, or G:F. Pigs receiving LPS had lower G:F, and greater RT and TNF-α during d 28-36 compared with non-challenged pigs (P < 0.01). Within the LPS-challenged pigs, there was no difference (P > 0.10) in ADG or ADFI among treatments (d 28-36, 0-42); however, pigs fed ZnHydroxyCl were more efficient (P < 0.02). RT and TNF-α at h 0 were similar (P > 0.10) among treatments. On d 36, 3 h following the last LPS injection, pigs fed ZnHydroxyCl had lower RT and TNF-α, followed by ZnO, then ZnSO4 (P < 0.10.) These data suggest that of the sources fed, pigs fed ZnHydroxyCl had greater performance and a lower immune response during a health challenge.