Effect of inorganic selenium supplementation on selenosis in postweaning swine

A total of 72 pigs weaned at 4 wk of age were allotted by litter and weight to nine treatment groups and fed 20% protein cornsoybean meal diets supplemented with various levels of inorganic Se during a 37-d postweaning period. Eight groups were fed diets with 0, 2.5, 5.0, 7.5, 10, 15, 20 or 40 ppm Se provided as sodium selenite, while a ninth was offered the 0- and 40-ppm Se diets in separate feeders. Gains and feed intakes were similar during the trial for the 0- and 2.5-ppm Se diets. Both gain and feed intake declined as dietary Se levels above 5.0 ppm increased. At a dietary Se concentration of 40 ppm, feed consumption ceased within a few days of feeding and subsequent gains were negative. Pigs offered both the 0- and 40-ppm Se diets preferentially selected the basal as compared with the 40-ppm Se diet. When the feeders were switched at 28 d they refused the 40-ppm Se diet within a few hours. After a 17-d period, pigs fed the 20- or 40-ppm Se diet were not able to coordinate their walk, with many exhibiting an inability to stand. Alopecia was demonstrated in pigs fed 15 ppm Se or higher at 17 d, but was evident in the 5.0-ppm group at 37 d. At the termination of the trial, abnormal hoof formation at the coronary band was evident in pigs fed diets containing Se greater than or equal to 5 ppm.