Ultrastructural alterations of the liver of Pekin ducks fed methyl mercury-containing diets.

This report describes the ultrastructural alterations of the liver of 24 male and 24 female Pekin ducks fed 0.0, 0.5, 5.0, and 15.0 ppm of methyl mercury chloride (MeHgCl), mixed in a mash diet, for 12 wk. Birds were weighed weekly and observed for neurologic symptoms daily. Samples of blood, liver, kidney, skeletal muscle and brain were analyzed for Hg residue by atomic absorption spectrophotometry. Livers were fixed in situ by perfusion with glutaraldehyde fixative and processed for electron microscopy. The percent decreases in mean body weights between wk 0 and wk 7 were statistically not significant except for males fed 5.0 ppm MeHgCl. Leg paralysis and convulsions in males treated with 15.0 ppm began at wk 5 and in females at wk 8, but were more severe in the latter. The dose-residue response for the three dose levels in all five tissues was linear, with liver and kidney containing the highest and the brain the least amount of Hg. Hepatocytes in 0.5- and 5.0-ppm MeHgCl treatment groups showed little morphologic changes, while liver cells in the 15.0-ppm group had several ultrastructural alterations, including remarkable increase in peribiliary lysosomal bodies. The mitochondria of some hepatocytes exhibited lysis of both inner and outer membranes. Changes also occurred in endothelial and Kupffer cells. These results indicate that dosing Pekin ducks with 15.0 ppm causes ultrastructural alterations indicative of toxic injury to the liver.