Toxicity of Prudhoe Bay crude oil to mallard duck (anas platyrhynchos) embryos
Lusimbo, Wanjala Simiyu
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This study was undertaken to assess rates and timing of mortality and hatchability, to identify pathological changes and compare them to those observed in chicken embryos, and to determine whether mallard duck chorioallantoic membrane (CAM) is a target organ of toxicity of Prudhoe Bay crude oil (PBCO). Mortality and hatchability were determined in embryos exposed to 10[mu]l of PBCO on days 3, 6, 9 and 12 of incubation. Pathological changes in embryos and the CAM, hematological parameters and body and plasma calcium concentration were assessed in live embryos exposed to PBCO on day 12. Oil-exposed embryos had high mortality, low hatchability and high prevalence of pathological changes. Mortality was characterized by initial death that coincided with development and maturation of the CAM and a sublethal effect that resulted in live, mature embryos, which were unable to hatch. This mortality at hatching contributed greatly to total mortality. Lesions included hepatic and renal necrosis, liver enlargement, subcutaneous edema, reduced body weight and ratio of body weight to fresh egg weight, short crown-rump, third toe and metatarsal lengths, depletion of lymphocytes in the bursa of Fabricius, renal hematopoiesis, and diffuse changes in the CAM which included necrosis and hyperplasia, of chorionic epithelium, soft swelling of mesenchymal cells, hemorrhages and reduced vascular density. There also were high proportions of reticulocytes and polychromatophilic and primary erythrocytes. Prevalence of lesions in the CAM was greatest during the stage of acute toxicity, suggesting that injury to the CAM may have a role in acute oil. toxicity. The distribution of lesions in the CAM suggests a direct effect on the CAM cells of toxic components or their metabolites. Injury to the CAM did not affect its role in mobilization of calcium from the eggshell. Body and plasma calcium in oil-exposed and control embryos were not different. Embryos exposed to PBCO did not develop anemia nor any damage to the red blood cells. The spectrum of morphological changes in oil-exposed embryos suggests retarded and altered development The rate and timing of mortality and pathological changes in oil-exposed mallard embryos were similar to those reported in oil-exposed chicken embryos.
DegreeDoctor of Philosophy (Ph.D.)
CommitteeWobeser, Gary A.; Leighton, Frederick A.
Copyright DateSeptember 1999