Studies On Pathology Of Zinc Toxicity In Chicken

The experiment was conducted with the object of study on pathology of zinc (Zn) toxicity in chicken. 200 one-day-old Avian broilers were randomly divided into four groups and fed on diets as follow: basic diet (Zn 100mg/kg, control) and toxic diet(Zn 1500mg/kg ,2000mg/kg ,2500mg/kg) for seven weeks . The chicken in groups II, III and IV grew very slowly.- At the same time , the affected chicken depressed and became lame.Histopathologically,lymphocytes of the thymus.bursa of Fabricius and spleen were significantly depleted,degenerated and necrotic.The serum Alkaline phosphatase activities in group II, the serum glutamic-pyruvic transaminase activities, amylase activities and Zinc concentrations in groups II, III and IV were much higher (p<0.05 or p<0.01) than those of group I. The serum creatine kinase activities, insulin activities in groups II, III and IV were also much higher. The serum calcium concentrations and Phosphorus concentrations were lower in groups II, III and IV than in group I. The serum total protein, albumin, globulin were also influenced by the levels of dietary zinc .Immunopathologically,the weight and growth index of lymphoid organs were significantly reduced in zinc toxic groups when compared with control group I. The GO/G1 phase of lymphocytes in the bursa of Fabricius,thymus and spleen was much higher,and. S,G2+M phases lower in zinc toxic groups than in group I. Compared with the control group I, the ANAE+ ratio of perpheral blood lymphocytes and erythrocyte C3bRR ratio markedly decreased and ICR ratio increased markedly.The proliferations of lymphocytes were impaired, and T-lymphocytes were decreased in peripheral blood.The humoral,cellular and erythrocyte immune function were reduced.