COMPARISON OF 4 ERYTHROCYTE FRAGILITY TESTS AS INDICATORS OF VITAMIN-E STATUS IN ADULT DOGS

Plasma α-tocopherol (α-T) concentrations, erythrocyte osmotic fragility and detergent sensitivity were measured at 8 week intervals in two 1-year-old male beagle dogs fed a vitamin E-deficient diet (<0·08 mg per kg α-T) and in two control beagles fed the same diet supplemented with vitamin E (>90 mg per kg α-T). Beginning at 24 weeks, dialuric acid haemolysis and spontaneous haemolysis were evaluated also. In the vitamin E-deficient dogs, plasma α-T concentrations declined progressively from baseline values of 20·5 and 31·3 μg per ml to 0·11 and 0·07 μg per ml, respectively, by 90 weeks. The supplemented dogs maintained α-T concentrations between 18·3 and 38·4 μg per ml. Both dialuric acid haemolysis (R = -0·89) and spontaneous haemolysis (R = - 0·91) increased with declining plasma α-T concentration. In the dialuric acid haemolysis assay, 50 per cent haemolysis occurred when plasma α-T declined to 1·7 μg per ml, compared with spontaneous haemolysis in which 50 per cent haemolysis occurred when plasma α-T declined to 0·5 μg per ml. Osmotic fragility and detergent sensitivity remained unchanged in the vitamin E-deficient dogs throughout the study. Of the four tests, dialuric acid haemolysis was the most sensitive in-vitro assay for vitamin E deficiency in adult dogs. © 1992.