Effects of shipping, handling, adrenocorticotropic hormone, and epinephrine on α-tocopherol content of bovine blood

Abstract

Summary In 2 studies, plasma, erythrocyte, and neutrophil α-tocopherol concentrations were monitored in beef cattle after shipping, handling, and sample collection. On the basis of α-tocopherol results, an additional 2 studies were designed to measure the effects of administration of adrenocorticotropic hormone (acth) and epinephrine on the α-tocopherol concentration in the aforementioned blood constituents and on creatine kinase (ck) activity in Holstein calves. In the first of these studies, 15 beef cattle that had recently arrived at the feedlot consumed feed supplemented daily with 1,000 IU of dl-α-tocopheryl acetate. Values for initial blood samples indicated that ck activity was high. Although plasma α-tocopherol concentration indicated that vitamin supplementation was adequate, rbc and neutrophil α-tocopherol values were generally nondetectable. After 4 weeks of supplementation, plasma α-tocopherol concentration increased (P < 0.05), and neutrophil and rbc α-tocopherol values became measurable in most of the cattle. In the second study, 6 beef heifers had decreased (P < 0.05) plasma, rbc, and neutrophil α-tocopherol values after multiple periods of handling and blood sample collection. In the third and fourth studies, 10 tamed Holstein heifer calves, 5 of which were administered acth and epinephrine to simulate stress effects on blood α-tocopherol concentrations and ck activity. In study 3, the vitamin E-adequate heifers had increased blood ck (P < 0.001) activity and cortisol (P < 0.01) concentration, and decreased (P < 0.05) neutrophil α-tocopherol concentration after hormone injections. In study 4, when vitamin E-deficient calves received the aforementioned hormones, ck activity increased (P < 0.05) and rbc α-tocopherol concentration decreased (P < 0.05), whereas plasma and neutrophil values did not change. These results indicate that shipping and handling, or the stress paradigm of acth and epinephrine injections, may reduce the α-tocopherol content of plasma, rbc, and neutrophils while increasing plasma ck activity, which indicates membrane destruction.