Pathology of the thymus, spleen and bursa of Fabricius in zinc-deficient ducklings

The weight and growth index of bursa of Fabricius, thymus and spleen were significantly reduced ( P< 0.05 or P< 0.01) in zinc (Zn)-deficient ducks (Zn 22.9 mg/kg diet) when compared with normal ducks. The G 0 /G 1 phase of the cell cycle of the bursa of Fabricius, thymus and spleen was much higher, and the S and G 2 +M phases lower in Zn-deficient ducks than in the controls. Histopathologically, there was lymphocyte degeneration and depletion of lymphoid organs, and the reticular cells of thymus were also degenerate or necrotic in the Zn-deficient group. The results demonstrated that Zn deficiency seriously inhibited the growth of lymphoid organs and caused marked pathology in the lymphoid organs. The results also showed that the effect of Zn deficiency on the primary lymphoid organs occurred earlier than on the secondary lymphoid organs. The effect of Zn deficiency was greatest on the bursa of Fabricius, followed by the thymus, and then the spleen.