Toxic effects of ingested lead shots in domestic fowls.

Lead poisoning from ingested shots is thought to be a major cause of high mortality in waterfowls throughout the world, and some millions of fowls die each year. However, there have been no other Japanese studies regarding lead toxicity in birds from ingested lead shots. We used domestic fowls instead of waterfowls as the experimental birds, in order to make clear the distribution and the toxic effects of lead shot in the birds. In a 1-wk follow-up study, two, four, and eight #4 lead shots were administered orally. A dose-dependent increase of the lead concentrations in blood, brain, liver, kidney, lung, spleen, bone, and epidermis of the gizzard was observed. In the 12-wk follow-up study, twenty domestic fowls were used and eight #4 lead shots were administered to the experimental birds. Lead concentrations in brain, liver, kidney, bone, ovary, fat tissue, and breast muscle increased more than in the 1-wk follow-up study. The observed lead concentrations of organs in the domestic fowls were lower than those of the other species used in past studies. The blood lead concentrations increased up to the third week and a remarkable suppression of delta-aminolevulinic acid dehydratase activity in red blood cells and elevation of free erythropoietic protoporphyrin were observed in the exposed group. Body weight loss, loss of hair, and neurological symptoms were also observed. However, there were no mortalities during the 1- and 12-wk studies.