title: The magnitude of lead toxicity in broiler chickens.
abstract: Four experiments were conducted to study the toxic effects of supplemental dietary lead (Pb) on broiler chickens from hatching to 42 d of age. Dietary variables were 0, 0.1, 0.5 or 1.0 mg Pb/kg feed as lead sulfate in Experiment 1, and 0, 0.5 or 1 mg Pb/kg feed as lead sulfate and lead acetate in Experiment 2. Experiments 3 and 4 were 2 x 4 factorial designs with 2 levels of calcium (0.65% or 1.30%) and 4 levels of Pb (0, 1, 10 or 100 mg Pb as lead sulfate/kg feed). Lead supplementation caused linear decreases in body weight gain in all experiments. In Experiments 1, 2 and 4, even 1 mg added Pb/kg feed caused significantly depressed body gains. Significant negative effects of added Pb on feed conversion ratios were found at 10 mg Pb/kg feed. Supplemental Pb caused a linear decrease in delta-aminolevulinic acid dehydratase (ALAD) activity. The higher level of calcium (1.30%) in the feed significantly reduced the negative effects of Pb on ALAD inhibition. Lead additions to the diet resulted in a dose-related increase of Pb in blood, kidney, liver and tibia. Higher dietary calcium caused reduced Pb in blood and liver. Lead is toxic to chickens at much lower levels than previously recognized.
authors.affiliation: Department of Poultry Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens 30602, USA.
authors.forename: R I
authors.initials: RI
authors.lastname: Bakalli
authors.forename: G M
authors.initials: GM
authors.lastname: Pesti
authors.forename: W L
authors.initials: WL
authors.lastname: Ragland
mesh_terms: D000821:Animal Feed; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002645:Chickens / Q000254:growth & development* / Q000378:metabolism*; D004912:Erythrocytes / Q000201:enzymology; D007668:Kidney / Q000378:metabolism; D007854:Lead / Q000378:metabolism; D007855:Lead Poisoning / Q000378:metabolism / Q000503:physiopathology / Q000662:veterinary*; D008099:Liver / Q000378:metabolism; D008297:Male; D009132:Muscles / Q000378:metabolism; D000623:Porphobilinogen Synthase / Q000097:blood; D011201:Poultry Diseases / Q000378:metabolism / Q000503:physiopathology*; D013977:Tibia / Q000378:metabolism
chemical_list: D007854:Lead; D000623:Porphobilinogen Synthase