Effect of Copper Toxicity on Lymphoid Organs in Ducklings

one-day-old Tianfu meat ducklings were divided into three groups, and fed on dietsas follows:(1)control (Cu 12.16 mg kg-1),(2) copper toxicⅠ(Cu 850 mg kg-1) and (3)copper toxicⅡ( Cu 1050 mg kg-1) for studies on effects of copper toxicity on lymphoidorgans in duckling with the methods of experimental pathology and flow cytometry (FCM).The weight and growth index of the thymus, spleen and bursa of Fabricius were markedlyreduced (P<0.05 or P<0.01) in both copper toxic groupⅠand Cu toxic group Ⅱ whencompared with control group. The G0/G1 phase of the cell cycle of the thymus, spleen andbursa of Fabricius was much higher, and S, G2+M phases lower in Cu toxic groupsⅠand Ⅱthan in the control group. There were lymphocyte degeneration and depletion of lymphoidorgans, and the reticular cells of spleen and bursa of Fabricius proliferated and thereticular cells of thymus were also degenerate and necrotic in Cu toxic groups. Theresults demonstrated that Cu toxicity seriously impaired the progression of lymphocytesfrom the G0/G1 phase to S phase, inhibited the development of lymphoid organs and causedmarked pathological injury in lymphoid organs. The results also showed that the effectof Cu toxicity on the primary lymphoid organs occurred stronger than on the secondarylymphoid organs. The effect of Cu toxicity was the greatest on the bursa of Fabricius,followed by the thymus, and then the spleen. Potential mechanisms underlying aforementionedobservation were also discussed.

Effect of Copper Toxicity on Lymphoid Organs in Broilers

The experiment was conducted to examine the effect of copper toxicity on lymphoid organs by experimental pathology andflow cytometry (FCM). 180 one-day-old Avian broilers were divided into three groups, and fed diets as follows: 1) Control(Cu 11.97 mg kg-1 diet), 2) Cu- toxic groupⅠ(Cu 650 mg kg-1) and 3) Cu- toxic groupⅡ(Cu 850 mg kg-1) for six weeks.Compared with the control, the growth index of the thymus, spleen and bursa of Fabricius were markedly reduced (P<0.05or P<0.01), the G0/G1 phase of cell cycles of the thymus, spleen and bursa of Fabricius was higher (P<0.05 or P<0.01), whilethe S phase and proliferating index were lower (P<0.05 or P<0.01) in both Cu-toxic group Ⅰ and Cu-toxic group Ⅱ. Theresults demonstrated that Cu toxicity seriously impaired the progression of lymphocytes from the G0/G1 phase to the Sphase, inhibited the growth and development of lymphoid organs.

Effect of Zinc Toxicity on Lymphoid Organs in Chickens

The experiment was conducted with the objective of studies on effects of zinc toxicity on lymphoid organs by the methods of experimental pathology and flow cytometry (FCM). 200 one-day-old Avian broilers were divided into four groups randomly, and fed on diets as follows: controls (Zn 100 mg kg-1)and zinc toxic (Zn 1 500 mg kg-1, zinc toxic group Ⅰ; Zn 2 000 mg kg-1, zinc toxic groupⅡ; Zn 2 500 mg kg-1, zinc toxic group Ⅲ) for seven weeks. The weight and growth index of the thymus, spleen and bursa of Fabricius were reduced in both zinc toxic groupⅡand zinc toxic group Ⅲ when compared with those of control group. The G0/G1 phase of the cell cycles of the lymphoid organs was higher, and S, G2+M phases lower in zinc toxic groups Ⅱand Ⅲ than in control group. Lymphocytes were depleted and degenerate in the lymphoid organs. The reticular cells of the bursa of Fabricius proliferated and the reticular cells of the thymus were also degenerate and necrotic, particularly in zinc toxic groups Ⅱand Ⅲ. The results demonstrated that more than 1 500 mg kg-1 impaired the progression of lymphocytes from the G0/Gl phase to S phase obviously, inhibited the development of lymphoid organs and caused marked pathological changes in the lymphoid organs. Potential mechanisms underlying these observations are also discussed.