Effect Of High Copper On Immune Function In The Chickens

420 one-day-old Avian chickens were randomly divided into seven groups, and fed on diets as follows: 1.control group(Cu 11mg/kg) and 2. high copper group(Cu 100mg/kg, high copper group â…  ; Cu 200mg/kg, high copper group â…¡ ; Cu 300mg/kg, high copper group â…¢; Cu 400mg/kg, high copper group â…£; Cu 500mg/kg, high copper group â…¤; Cu 600mg/kg, high copper group â…¥)respectively for six weeks.Chickens grew fastest in high copper groups â…  and â…¡, and lowest in both high copper groups â…¤ and â…¥ among seven groups. The signs began to appear in high copper group â…¤ at 4 weeks of age and in high copper group â…¥ at 3 weeks of age. Some of affected chickens died during the experiment.Pathologically, the bursa of Fabricius, spleen and thymus had no obvious change in high copper groups â…  and â…¡ when compared with control group. Lesions appeared in high copper groups â…¢, â…£, â…¤ and â…¥.Lymphocytes were decreased and reticular cells were proliferated in the medulla of lymphoid follicle of the bursa of Fabricius.lymphocytes of the spllen decreased in number in the white pulp.The thymus corpuscle is enlarged. Ultrastructurally, the bursa of Fabricius, spleen and thymus had no obvious change in high copper groups â…  and â…¡ when compared with control group.Quantities of apoptotic lymphatic cell increased in high copper groups â…¢,â…£ , â…¤, â…¥ while content of copper increased,and the mitochondria of lymphocytes were swelled and rough-surfaced endoplasmic reticulum were enlarged.Immunopathologically, the weight and growth index of lymphoid organs were significantly reduced in high copper groups â…¢, â…£,â…¤,â…¥ when compared with control group.The Go/G₁ phase of cell cycle of bursa of Fabricius,thymus and spleen was much higher, and S,G₂+M phases lower in high copper groups â…¢,â…£,â…¤,â…¥ than in control group. In comparation with the control group, the serum IL-2 and immunoglobulin contents , the ANAE positive and CD₄⁺/CD₈⁺ ratio of peripheral blood lymphocytes in high copper groups â…¢, â…£,â…¤,â…¥ decreased significantly.Precentage of apoptotic lymphocytes increased when compared with control group.The aforementioned results demonstrated high copper groups â…  and â…¡ promoted growth of the chickens and enhanced immune functions.High copper groups â…¢ and â…£ had no obvious effects on growth of the chickens,but immune function of chickens decreased.High copper groups â…¤ and â…¥ restrained the growth of the chickens in varying degrees and reduced immune function.