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This Article Full Text (PDF) All Versions of this Article: jas.2007-0403v1 86/11/3069    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Legleiter, L. R. Articles by Liu, H. C. Search for Related Content PubMed PubMed Citation Articles by Legleiter, L. R. Articles by Liu, H. C.

Copper deficiency in the young bovine results in dramatic decreases in brain copper concentration but does not alter brain prion protein biology

Department of Animal Science and Interdepartmental Nutrition Program, North Carolina State University, Raleigh, NC

Jerry_Spears{at}ncsu.edu

Abstract

A manganese (Mn) for copper (Cu) substitution on cellular prion proteins (PrP^c) in the brain that results in biochemical changes to PrP^c has been implicated in the pathogenesis of transmissible spongiform encephalopathies. Recent research in the mature bovine does not support this theory. The present study tested this hypothesis using progeny from gestating cows receiving Cu-deficient diets or Cu-deficient diets coupled with high dietary Mn. Copper-adequate cows (n = 39) were assigned randomly to treatments: 1) control (adequate in Cu and Mn), 2) Cu-deficient (-Cu), and 3) Cu-deficient plus high dietary Mn (-Cu+Mn). Cows assigned to treatments -Cu and -Cu+Mn received no supplemental Cu and were supplemented with molybdenum (Mo) to further induce Cu deficiency. The -Cu+Mn treatment also received 500 mg supplemental Mn/kg dietary DM. Calves were weaned at 180 d and maintained on the same treatments as their respective dams for 260 d. Copper-deficient calves (-Cu and -Cu+Mn) had decreased (P = 0.001) brain (obex) Cu and tended to have increased (P = 0.09) obex Mn relative to controls. Obex Mn/Cu ratios were substantially increased (P < 0.001) in calves receiving -Cu and -Cu+Mn treatments compared to controls and were higher (P < 0.001) in -Cu+Mn calves than in -Cu calves. Obex prion protein characteristics, including proteinase K degradability, superoxide dismutase (SOD)-like activity, and glycoform distributions, were largely unaffected. Obex tissue antioxidant capacity was not compromised by perturbations in brain metals, but Cu-deficient calves tended to have decreased (P = 0.06) Cu/Zn SOD activity and increased (P = 0.06) Mn SOD activity. Although obex copper was decreased due to Cu deficiency and Mn increased due to exposure to high dietary Mn, the obex metal imbalance had minimal effects on PrP^c functional characteristics in the calves.

Key Words: Bovine • Copper • Manganese • Prion