Submitted to: Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: 4/17/1999
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: In a pilot study, pigs fed a purified diet adequate in iron and marginally deficient in magnesium (Mg) had twice as many deaths from cardiac failure when manganese (Mn) was high (50 mg/kg) as compared to pigs fed low Mn (2 mg/kg). The present study examined the effect of marginal dietary Mg deficiency and high dietary Mn on the tissue distribution of Mg and Mn in an attempt to determine the cause of the deaths. Crossbred barrow pigs (n = 20) were fed for five weeks, in individual pens, one of 4 corn-based diets: diet 1 - 100 mg/kg Mg, 2 mg/kg Mn; diet 2 - 100 mg/kg Mg, 50 mg/kg Mn; diet 3 - 100 mg/kg Mg, 50 mg/kg Mn, and ultra-trace mineral (UT) mix; diet 4 - 1000 mg/kg Mg, 50 mg/kg Mn, and UT mix. After five weeks, animals were euthanized and tissues collected. Mn and Mg concentrations were determined by atomic absorption spectrometry. Mn concentrations in both the liver and skeletal muscle were significantly elevated by increased dietary Mn (p<0.05), but not by either UT addition or increased Mg in the diet. Increased dietary Mn did not affect heart Mn, but heart Mg concentrations were significantly (p=0.006) depressed by high, as compared to low, dietary Mn (941 +/- 81 and 795 +/- 65 ug Mg/g for diets 1 and 2, respectively). Dietary Mn did not affect Mg concentrations of any other tissues or fluids measured. Plasma Mg was significantly increased by increased dietary Mg (3.4 +/- 0.9 and 19.8 +/- 3.7 ug Mg/g for diets 3 and 4, respectively). These data suggest that high dietary Mn may exacerbate Mg-deficiency in heart muscle, and thus may be a complicating factor in the etiology of heart disease observed in some Mg deficient animals.