Sublethal effects of chronic lead ingestion in mallard ducks.
Mallard drakes (Anas platyrhynchos) fed 1, 5, or 25 ppm lead nitrate were bled and sacrificed at 3-wk intervals. No mortality occurred, and the pathologic lesions usually associated with lead poisoning were not found. Changes in hematocrit and hemoglobin concentration did not occur. After 3-wk ducks fed 25 ppm lead exhibited a 40% inhibition of blood delta-aminolevulinic acid dehydratase activity that persisted through 12 wk exposure. After 12 wk treatment similar enzyme inhibition was present in the ducks fed 5 ppm lead. At 3 wk there was a small accumulation of lead (less than 1 ppm) in the liver and kidneys of ducks fed 25ppm lead; no further increases occurred throughout the exposure. No significant accumulation of lead occurred the the tibiae or wing bones. Groups of ducks fed 5 and 25 ppm diets for 12 wk were placed on clean feed and examined through a 12 wk posttreatment period. After 3 wk on clean diet delta-aminolevulinic acid dehydratase activity and lead concentrations in the blood had returned to pretreatment levels. Even though lead concentrations in the blood, soft organs and bone were low, a highly significant negative correlation between blood lead and blood enzyme activity was obtained. This enzyme bioassay should provide a sensitive and precise estimate for monitoring lead in the blood for waterflow.
D000821:Animal Feed / Q000032:analysis; D000818:Animals; D004032:Diet; D004372:Ducks / Q000502:physiology*; D006400:Hematocrit; D006454:Hemoglobins / Q000032:analysis; D007854:Lead / Q000032:analysis / Q000097:blood / Q000378:metabolism; D007855:Lead Poisoning / Q000201:enzymology / Q000503:physiopathology*; D008297:Male; D000623:Porphobilinogen Synthase / Q000378:metabolism; D013997:Time Factors
D006454:Hemoglobins; D007854:Lead; D000623:Porphobilinogen Synthase