Cobalt supplied per os reduces the mammary Δ9-desaturase index of bovine milk1

Abstract

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 Delta (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 < or = 0.01) on fatty acids that were products of Delta(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 Delta (9)-desaturase, only 18:0 increased (P < 0.001) in all groups supplied with Co-containing solutions. Thus, Co had a reducing effect (P < or = 0.004) on the Delta (9)-desaturase indices [(product of Delta(9)-desaturase)/(product of Delta(9)-desaturase + substrate of Delta(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 Delta(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 Delta(9)-desaturase indices of bovine milk.

ORIGINAL ARTICLE: Intravenous injections of cobalt reduce fatty acid desaturation products in milk and blood of lactating cows

“…This study confirmed the results of Shingfield et al. (2008) and Taugbøl et al. (2008), who found that a high amount of ruminal or per os supplemented Co reduced the Δ 9 ‐desaturase indices in bovine milk fat.…”

“…Within each Latin Square, treatment was administered on days 1–5, and days 6–14 were the depuration period. Treatment 1 consisted of per os supplementation of 0.25 l of a 9 g/l solution of Co‐acetate twice daily, corresponding to 3.5 g Co per day (Taugbøl et al., 2008). In Treatment 2, 450 mg Co‐acetate diluted in 250 ml 0.9% saline solution was injected into the jugular vein twice daily, at 8:00 and 15:30 hours.…”

“…Theoretical response factors for flame ionization detectors have been used for all FAME (Ackman and Sipos, 1964; Wolff, 1995). The methods used for fatty acid analyses in blood plasma have been described by Taugbøl et al. (2008).…”

“…Cobalt‐EDTA has been used as a liquid marker since 1980 (Uden et al., 1980). Recently published papers have shown that high amounts of Co‐EDTA, used as a marker and introduced into the rumen for 7 days, or per os as Co‐EDTA and Co‐acetate for 5 days, reduce Δ 9 ‐desaturase indices of bovine milk fat (Shingfield et al., 2008; Taugbøl et al., 2008). However, it remains unknown whether these reductions are the direct result of absorbed Co or through the effect of Co on digestion and delivery of substrates involved in mammary fat synthesis.…”

Stearoyl-CoA Desaturase Genes in Lipid Metabolism

“…In particular, the high response of milk trans-9, trans-11-CLA in goats receiving sunfl ower oil could play a direct role in the typical decrease of milk FA desaturation ratios in this animal species (Table 13.2 ). Otherwise, abomasal infusions in cows and ewes (Griinari et al 2000 ;Corl et al 2001 ;Kay et al 2004 ;Bichi et al 2012 ) of sterculic oil, known as a strong inhibitor of SCD, and administration of Co-EDTA in the rumen or per os (Shingfi eld et al , 2008aTaugbøl et al 2008Taugbøl et al , 2010Karlengen et al 2012 ) decreased the milk FA desaturation ratios without alteration of mammary SCD1 mRNA abundance (Karlengen et al 2012 ) and without decreasing milk fat secretion. It was hypothesized (Shingfi eld et al 2008a ) that Cobalt interferes with the transfer of electrons from cytochrome b5 to the di-iron protein center of the terminal desaturase protein, thus altering the oxidation-reduction reactions of the conversion of the acyl-CoA substrates.…”