The present study investigated the potential consequences, positive or negative, that selection for favorable production-related traits may have on concentrations of vitamin B-12 and key chemical elements in dairy cow milk and serum and the possible impact on milk healthiness, and associated benefits, for the dairy product consumer. Milk and serum samples (950 and 755, respectively) were collected from Holstein-Friesian dairy cows (n = 479) on 19 occasions over a 59-mo period, generating 34,258 individual records, and analyzed for concentrations of key trace and quantity elements, heavy metals, and milk vitamin B-12. These data were then matched to economically important production data (milk, fat, and protein yield) and management data (dry matter intake, liveweight, and body condition score). Multivariate animal models, including full pedigree information, were used to analyze data and investigate relationships between traits of interest. Results highlighted negative genetic correlations between many quantity and trace elements in both milk and serum with production and management traits. Milk yield was strongly negatively correlated with the milk quantity elements Mg and C-a (genetic correlation between traits, r(a) = -0.58 and -0.63, respectively) as well as the trace elements Mn, Fe, Ni, Cu, Zn, and Mo (r(a) = -0.32, -0.58, -0.52, -0.40, -0.34, and -0.96, respectively); and in serum, Mg, Ca, Co, Fe, and Zn (r(a) = -0.50, -0.36, -0.68, -0.54, and -0.90, respectively). Strong genetic correlations were noted between dry matter intake with V (r(a) = 0.97), Fe (r(a) = -0.69), Ni (r(a) = -0.81), and Zn (r(a) = -0.75), and in serum, strong negative genetic correlations were observed between dry matter intake with Ca and Se (r(a) = -0.95 and -0.88, respectively). Body condition score was negatively correlated with serum P, Cu, Se, and Pb (r(a) = -0.45, -0.35, -0.51, and -0.64, respectively) and positively correlated with Mn, Fe, and Zn (r(a) = 0.40, 0.71, and 0.55, respectively). Our results suggest that breeding strategies aimed at improving economically important production-related traits would most likely result in a negative impact on levels of beneficial nutrients within milk for human consumption (such as Mg, Ca, Fe, Zn, and Se).

Atherosclerosis-related cardiovascular disease (CVD) represents a great burden to human health.Inflammation and oxidative stress have both been implicated in playing important roles in the development of atherosclerosis and in addition, diet also plays a significant role in modulating the disease process.In this study, the role played by two dietary components, vitamin D and selenium (Se) both individually and together, have been investigated in a cellular model of atherosclerosis.Vitamin D is a known modulator of immune function in addition to its classical effects on calcium and bone homeostasis (1) whereas Se, mainly through its incorporation into selenoproteins, plays an important anti-oxidant role (2) .Each of these micronutrients, which are known modulators of immune function and oxidative stress respectively, therefore potentially play a role in influencing atherosclerotic development.We hypothesised that in both immune cells and endothelial cells, vitamin D could potentiate the function of Se and conversely, that Se promoted the action of vitamin D and that these interactions would influence atherosclerosis.Potential interactions between both nutrients were assessed by measuring the effect of each nutrient on the expression of genes (by qPCR) known to be involved in the action of the other nutrient (i.e.cystathionine beta-synthase (CBS) for Se and 25-hydroxyvitamin D 3 1-alpha-hydroxylase (CYP27B1) for vitamin D).CBS is the enzyme that converts homocysteine to cystathionine but which is also involved in incorporating Se into selenoproteins, and CYP27B1 converts 25-hydroxyvitamin D 3 (25(OH)D 3 ) to its active 1,25(OH) 2 D 3 form.In addition, the effect of vitamin D on Se function was assessed by assaying its effect on glutathione peroxide activity (GPx) in immune cells.Lastly, the effect of both micronutrients on basal and pro-inflammatory-induced adhesion of monocytes to endothelial cells was assayed by an in vitro adhesion assay.Human monocytes (U937 cells) were cultured with or without Se and/or 25(OH)D 3 and the expression of CYP27B1 and CBS quantified.Additionally, GPx activity was measured in cell lysates.For the monocyte-endothelial adhesion assay, HUVECs were stimulated with and without TNF-α and adhesion of U937 cells quantified by fluorescence.Results showed that Se augmented the expression of CYP27B1 (Fig A; p < 0.001) and also that CBS expression was upregulated by vitamin D (p < 0.01; data not shown).GPx activity at suboptimal Se concentrations was shown to be stimulated by 25(OH)D 3 to levels achieved with optimal Se (Fig B; p < 0.01).Se was shown to attenuate both basal and cytokine-stimulated adhesion of monocytes to endothelial cells and that the presence of vitamin D further reduced basal adhesion (Fig C; p < 0.05).Data are represented as means ± SEM (n = 3).Student's t-test was used to determine differences between treatments, *p < 0.05, **p < 0.01, ***p < 0.001, ns: not significant.In conclusion, the presence of Se may act to enhance localised levels of active vitamin D and conversely, vitamin D may act to enhance Se status.This study therefore provides the first evidence for a potential synergistic interaction of vitamin D and Se which together may enhance both immune and endothelial function and slow atherosclerotic development.