The experiment was conducted to examine the effect of dietary copper excess on lymphoid organs by the methods of experimental pathology and flow cytometry （FCM）. A total of 350 one-day-old avian broilers were divided into seven groups and fed on diets as follows： 1. control group （Copper 11 mg/kg.diet）, 2. Copper excess （Copper 100 mg/kg, copper excess group I; copper 200 mg/kg, copper excess group II; copper 300 mg/kg, copper excess group III; copper 400 mg/kg, copper excess group IV; copper 500 mg/kg, copper excess group V; copper 600 mg/kg, Cu excess group VI） for 6 wk. The weight and growth index of the thymus, spleen and bursa of Fabricius were obviously decreased （ P 〈 0.05 or P 〈 0.01 ） in the copper excess groups III, IV, V and VI, and were lightly increased in both the copper excess group I and copper excess group II when compared with those of the control group. The G0/G1 phase of the cell cycles of the aforementioned lymphoid organs was higher （ P 〈 0.05 or P 〈 0.01 ）, and S, G2 ＋ M phases and proliferating index lower （ P 〈 0.05 or P 〈 0.01 ） in the copper excess groups III, IV, V and VI than in the control group, copper excess group I and copper excess group I1. At the same time, it was also observed that the number of lymphocytes was decreased in the lymphoid organs in the copper excess groups III, IV, V and VI, The results demonstrated that dietary copper in excess of 200 mg/kg, diet impaired the progression of lymphocytes from G0/G1 phase to S phase obviously, inhibited the development of lymphoid organs and caused pathological changes in the lymphoid organs, and that copper of 100 and 200 mg/kg-diet was helpful for the development of the lymphoid organs. Potential mechanisms underlying the aforementioned observations are discussed.
CUI Heng-min XU Zhi-yong PENG Xi DENG Jun-liang ZHU Kui-cheng
Experimental study was conducted to examine the effect of copper excess on the peripheral blood T-lymphocyte by the methods of flow cytometry （FCM） and experimental pathology. 420 one-day-old Avian chickens were randomly divided into seven groups, and fed on diets as follows： 1. controls （Cu 11mg/kg） and 2. copper excess （ Cu 100mg/kg, copper excess group Ⅰ; Cu 200mg/kg, copper excess group Ⅱ; Cu 30（hng/kg, copper excess group Ⅲ; Cu 400mg/kg, copper excess group Ⅳ; Cu 500mg/kg, copper excess group Ⅴ; Cu 600mg/kg, copper excess group VI） for six weeks. The results were as follows- 1 ） In thymus, lymphocytes in the medulla were decreased in number in copper excess groups Ⅲ,Ⅳ,Ⅴ, and Ⅵ, and the increased and enlarged thymic corpuscles and the proliferated reticular cells were also observed in both copper excess group V and copper excess group VI in comparison with those of control group. 2） The percentage of CD4＋ T cells was markedly decreased from 2 to 6 weeks of age in copper excess groups Ⅳ, Ⅴ and Ⅵ （P 〈0.05 or P 〈0.01）. 3） The percentage of CD8＋ T cell was not varied in six copper excess groups during the experiment when compared with that of control group （ P 〉 0.05 ）. 4） The CD4 ＋ / CD8＋ ratio was lower from 2 to 6 weeks of age in copper excess groups Ⅳ, Ⅴ and VI than in control group （ P 〈0.05 or P 〈0.01）. 5） It was concluded that dietary copper in excess of 300mg / kg suppressed the development of T-lymphocytes and reduced the percentage of CD4＋ T cells and the CD4＋/CD8＋ ratio, and resulted in pathological injury of the thymus. Cellular immune function was finally impaired.
