Experimentally induced vitamin E-selenium deficiency in the growing dog.

Eight 5-to 8-week-old Beagle pups were allotted to 4 groups of 2 dogs each. For 55 to 70 days, they were fed either a semisynthetic basal diet (BD) deficient in vitamin E and selenium (Se) (group 1) or the BD supplemented with either 30 IU alpha-tocopherol/kg (group 2), 0.5 ppm Se as selenite (group 3), or 1.0 ppm Se as selenite (group 4). In the dogs fed the BD, clinical signs of vitamin E-Se deficiency developed after 40 to 60 days. These signs were accompanied by increased plasma activity of creatine phosphokinase (CPK) and glutamic oxalacetic transaminase (GOT). The dogs were euthanatized after 10 to 15 days of progressive clinical signs, including muscular weakness, subcutaneous edema, anorexia, depression, dyspnea, and eventual coma. Gross lesions seen at necropsy included ventral subcutaneous edema, generalized skeletal muscular pallor and edema with scattered white longitudinal streaking, prominent brownish yellow discoloration of the intestinal musculature, and a layer of white chalky material at the renal corticomedullary junction. Microscopically, there was evidence of extensive skeletal muscular degeneration and regeneration, focal subendocardial necrosis in the ventricular myocardium, intestinal lipofuscinosis, and renal mineralization. Mean hepatic Se content in the dogs fed the BD was 0.10 ppm (wet weight basis) at necropsy. In the dogs fed the 3 supplemented diets, clinical signs of deficiency did not develop. At necropsy, mild skeletal myopathy was evident histologically in the dogs fed BD and 0.5 ppm Se (group 3) but not in the dogs fed the other supplemented diets. Intestinal lipofuscinosis was found in the dogs fed the 3 supplemented diets but was less severe in the dogs fed the diet supplemented with vitamin E than in those fed diets supplemented with Se.