Vitamin E Deficiency and Fat Stress in the Dog

Abstract

Thirty-two male beagle puppies were fed vitamin E-deficient diets with four levels (1, 5, 10, and 15%) of safflower oil with or without a vitamin E supplement for a 15-week period. The unsupplemented dogs developed a vitamin E deficiency which was correlated with increased dialuric acid hemolysis of red cells and decreased plasma tocopherol values. Both hemoglobin and packed cell volume were depressed by increasing fat consumption, unrelated to tocopherol supplementation and attributed to in vivo red cell disruption. Creatine phosphokinase values were elevated in tocopherol-deficient dogs and were correlated with fat consumption. Terminal plasma vitamin A concentrations were lower in dogs receiving more than 1% supplementary fat. At necropsy, browning of the intestinal muscularis in the tocopherol-deficient dogs was related to the consumption of polyunsaturated fats (PUFA). Microscopically, lipofuscin was seen in smooth muscle of gut, urinary bladder and small arterioles. Neuroaxonal dystrophy and myodegeneration were also found in the vitamin E-deficient dogs. The requirement for tocopherol was directly related to PUFA consumption, apparently associated with the metabolism of the fat and not with an antioxidant role of the vitamin.