Pathology of dimethylnitrosamine poisoning in pekin ducklings

Abstract

Summary Pekin ducklings were fed a purified diet containing dimethylnitrosamine at levels of 0.02% and 0.0175%. The level of 0.02% was acutely toxic, weight gains were significantly reduced, and feeding was discontinued after 3 weeks. Abdominal distention was observed in some ducks fed 0.0175% dimethylnitrosamine for 4 weeks. A nonhemorrhagic ascites and hydropericardium were observed at necropsy in both test groups. The livers were atrophic and gray in color. The spleens of ducks fed for 4 weeks were markedly enlarged. Histopathologic lesions in the liver included necrosis of hepatocytes with condensation of the reticulum, bile duct proliferation, bile ductule cell hyperplasia, and thickening of the liver capsule with an increase in reticular fibers. Lymphoid hyperplasia was especially prominent in the ducks fed dimethylnitrosamine for 3 weeks. The lymphocytes were present as nodules and as a diffuse infiltration of cells around radicles of the portal vein. Degeneration and necrosis was observed in the lymphoid tissue of ducks fed 4 weeks. Hyalinization of renal glomeruli was prominent in all ducks, and the hyaline material was strongly PAS-positive but was negative to Congo Red, Oil Red O, and the Ziehl-Nielsen stain. Enlargement of the spleen was restricted to ducks fed 4 weeks. Much of the red pulp of the spleen was replaced by large pale cells with vacuolated granular cytoplasm. This change was considered to be hyperplasia of the reticuloendothelial components of the spleen.