Effects of a Chronic Lipopolysaccharide Challenge on Growth Performance and Immune Response of Nursery Pigs Fed Differing Sources and Concentrations of Copper, Manganese, and Zinc

Recent results from our lab suggest that hydroxychloride sources of Cu, Mn and Zn reduced serum pro-inflammatory cytokines following an acute immune challenge. However, growth performance was not affected by mineral source. Therefore, a study was conducted to determine the effects of source and concentrations of Cu, Mn and Zn on growth performance and immune response during a chronic lipopolysaccharide (LPS; Escherichia coli O111:B4) challenge. Weaned pigs (N = 495; 5.4 kg) were blocked by BW and randomly allotted to 1 of 5 treatments arranged as a 2 x 2 factorial plus a control (9 reps/trt). The 4 treatments exposed to an LPS challenge consisted of two mineral sources (sulfate or hydroxychloride) and two mineral concentrations (5, 16 and 50; or 10, 32 and 100 ppm of Cu, Mn, and Zn). The control pigs were unchallenged and fed the low sulfate diet. All pigs were fed a common diet from d 0 to 7, then fed treatment diets from d 7 to 42. On d 29, 31, 33 and 35 of the study, challenged pigs were injected intramuscularly with LPS (15 ug/kg BW). Pigs and feeders were weighed to determine ADG, ADFI, and G:F. Body weight, rectal temperature (RT) and blood samples were taken before the first LPS injection and 3 h post-injection on the final day. Data were analyzed as a randomized complete block design with effects of source, concentration, and their interaction tested plus LPS vs. control. Prior to LPS challenge (d 7-28), there were no effects (P > 0.10) of trt on ADG, ADFI, or G:F. Following LPS (d 28-42), ADG and ADFI were reduced (P < 0.001) by 12 and 9% for pigs challenged with LPS. Pigs fed hydroxychlorides had greater (P < 0.05) ADG and ADFI compared with those fed sulfates. There was no effect (P > 0.10) of mineral concentration on growth performance. RT and TNF-alpha following the final LPS injection were increased (P < 0.001) for pigs administered LPS vs. control. Pigs fed the higher concentrations of minerals had lower (P < 0.05) RT compared with those fed the lower concentrations. TNF-alpha tended to be decreased (P < 0.10) at h 0 and 3 for pigs fed hydroxychlorides vs. those fed sulfates. There were no source by concentration interactions. Pigs fed hydroxychloride sources had improved growth performance and tended to have lower TNF-alpha following a chronic immune challenge vs. those fed sulfate sources.