Effect of excess dietary manganese on lipid composition of calf blood plasma, heart, and liver.

Preruminant calves were fed milk replacer containing control (40 ppm) or two high concentrations (200 and 1000 ppm) of Mn to assess the effect of excessive Mn intakes on plasma, heart, and liver lipids. The two higher Mn intakes had no effect on lipid classes in liver and heart, except for elevated triglycerides in liver and lower sphingomyelin in heart (for 1000 ppm of Mn). At 1000 ppm of Mn intake, but not at 200 ppm, marked increases occurred in plasma total lipids, phosphatidylcholine, cholesterol, cholesterol esters, sphingomyelin, and triglycerides. The highest intake altered the essential fatty acid composition of liver phosphatidylcholine. Linoleic and linolenic acids were increased, but arachidonic and eicosapentaenoic acids were decreased, suggesting that very high excess of Mn interfered with hepatic desaturation and elongation of the essential fatty acids. Thus, high Mn intake (200 ppm) caused relatively few tissue lipid changes, whereas very high intake (1000 ppm) markedly increased plasma lipid classes and apparently interfered with essential fatty acid metabolism in liver.