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This Article Full Text Full Text (PDF) All Versions of this Article: jas.2007-0372v1 86/11/3062    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 Taugbøl, O. Articles by Harstad, O. M. Search for Related Content PubMed PubMed Citation Articles by Taugbøl, O. Articles by Harstad, O. M.

Cobalt supplied per os reduces the mammary ⁹-desaturase index of bovine milk¹

O. Taugbøl^*,2, I. J. Karlengen^*, T. Bolstad^*, A. H. Aastveit and O. M. Harstad^*

^* Department of Animal and Aquaculture Sciences, and Department of Chemistry, Biotechnology and Food Science, Section for Bioinformatics and Analytical Methods, Norwegian University of Life Sciences, 1432 Ås, Norway

² Corresponding author: ole.taugbol{at}umb.no

Results indicated that the dual marker system of Yb-acetate and Co-EDTA supplied per os reduced the proportion of fatty acids in bovine milk that were products of ⁹-desaturase. To verify this effect and identify the responsible marker component, 18 cows (3 cows per treatment) were administered per os a 0.25-L solution of either Co-acetate, Co-EDTA, Co-EDTA + Yb-acetate, EDTA, Yb-acetate, or water twice daily for 5 d. The daily amounts of Co, Yb, and EDTA were, respectively, 3.50, 3.44, and 21.00 g per cow. Milk and blood were sampled and analyzed for content of fatty acids, and blood was sampled and analyzed for Co and cobalamin. Only solutions containing Co had a reducing effect (P 0.01) on fatty acids that were products of ⁹-desaturase in milk—cis-9 10:1, cis-9 14:1, cis-9 16:1, cis-9, trans-11 18:2, and cis-9 18:1—with the exception of the solution containing Co-EDTA + Yb-acetate for cis-9 18:1. Of the substrate fatty acids of ⁹-desaturase, only 18:0 increased (P < 0.001) in all groups supplied with Co-containing solutions. Thus, Co had a reducing effect (P 0.004) on the ⁹-desaturase indices [(product of ⁹-desaturase)/(product of ⁹-desaturase + substrate of ⁹-desaturase)] of milk for cis-9 14:1, cis-9 16:1, cis-9 18:1, and cis-9, trans-11 18:2. There were no differences in ⁹-desaturase indices between Co-EDTA and Co-acetate. None of the marker solutions influenced the fatty acid composition of blood plasma, and Co was detected only in the blood samples from cows treated with solutions containing Co. On the basis of these results, we concluded that Co given per os decreased the ⁹-desaturase indices of bovine milk.

Key Words: bovine milk • cobalt • ⁹-desaturase • oleic acid • rumenic acid • stearoyl-coenzyme A desaturase