58 The Effect of Altering Dietary Manganese and Selenium Levels on the Growth Performance and Blood Manganese-superoxide Dismutase Activity in Nursery Pigs

Abstract

Abstract The objective of this study was to determine the effect of altering dietary levels of manganese and selenium on growth performance and MnSOD specific activity. Weaned piglets were blocked by weight (n = 216; 5.21 ± 1.17 kg; 21 ± 3 d) and sex (2 barrows and 2 gilts/pen). Pens within a block were randomly assigned to dietary treatments in a factorial design with main effects of Se (0.1 and 0.3 ppm) and Mn (0, 12, and 24 ppm). Diets (n = 9 pens/treatment) were fed in three phases (P1 = d 1–7, P2 = d 7–21, P3 = d 21–35). Pigs and orts were weighed weekly and pigs were bled on d 0, 7, 21, and 35 for analysis of specific activity of red blood cell MnSOD. Data were analyzed as 2x3 factorial design via SAS PROC GLM. There were no Se effects or Mn x Se interactions observed. There was a linear increase (P < 0.05) in overall ADG (397, 424, and 438 g day-1pig-1 for 0, 12, 24 ppm Mn, respectively). There was a linear trend (P < 0.1) in overall ADFI (557, 560, 592 g day-1pig-1 for 0, 12, 24 ppm Mn, respectively). Feed efficiency (d 0–35) across increasing Mn levels were 0.71, 0.76, 0.74 (P > 0.1). MnSOD activity in RBC increased from d 0–7, peaked on d 7 and decreased to d 35. On d 7, diets with 12 and 0 ppm Mn had significantly increased (P < 0.05) MnSOD activity (0.91 and 0.87 IU mg-1 protein, respectively) compared to diets with 24 ppm Mn (0.67 IU mg-1 protein). The dietary treatment that best maintained MnSOD activity was 0.3 ppm Se and 12 ppm Mn supplemented, while ADG was maximized in the diet with 0.3 ppm Se and 24 ppm Mn supplementation.