Efficacy and safety of selenium-vitamin E injections in newborn pigs to prevent subclinical deficiency in growing swine.

Seventy-eight newborn pigs were allotted to 4 treatment groups: 22 pigs in group A were given no selenium-vitamin E (Se-E), 22 pigs in group B were given small doses of Se-E, 22 pigs in group C were given medium doses of Se-E, and 12 pigs in group D were given large doses of Se-E. Pigs were intramuscularly injected before 7 days of age and at weaning (40 days of age), respectively, as follows: group A--1 ml of physiologic saline solution/pig each time, group B--0.25 mg of Se/pig and later 0.06 mg of Se/kg of body weight, group C--1.0 mg of Se/pig and later 0.24 mg of Se/kg, and group D--1.5 mg of Se/pig and later 0.72 mg of Se/kg. Selenium was supplied as sodium selenite in commercially available Se-E injectable compounds. From 2 weeks of age to weaning, the pigs were fed a corn-torula yeast creep feed containing Se at the concentration of 0.03 ppm, and from weaning to slaughter, a corn-soybean meal ration was fed containing Se at the concentration of 0.07 ppm and alpha-tocopherol at the concentration of 15.7 mg/kg. Subclinical Se-E deficiency developed in control pigs of group A and was characterized by subtle muscular stiffness, significant increases in plasma activities of glutamic oxalacetic transaminase (GOT) and creatine phosphokinase (CPK), and typical residual lesions in heart and skeletal muscle, but not in liver, at slaughter at 165 days of age. Pigs injected with Se-E did not develop these evidences of subclinical deficiency. Pigs in group D were stunted for several weeks after the 2nd Se-E injection, and plasma GOT and CPK activities were significantly increased at 3 weeks after injection. Growth rates were otherwise similar between groups. Significant difference in Se content of liver, muscle, serum, and hair was not seen between pigs in the 4 groups at 120 and 165 days of age. A test period of physical exertion and heat stress resulted in significant increase of plasma GOT and CPK activities in 4 of 8 pigs at 110 days of age.