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.