ABSTRACT
The experiment was conducted to examine the effect of zinc toxicity on the peripheral blood T-lymphocyte by the method of flow cytometry(FCM) and ANAE.200 one-day-old Avian broilers were divided into four groups,and fed with the diets as follows:①control group(Zn 100 mg/kg diet) and ② zinc toxic groups(Zn 1 500 mg/kg diet,zinc toxic group Ⅰ;Zn 2 000 mg/kg diet,zinc toxic group Ⅱ;Zn 2 500 mg/kg diet,zinc toxic group Ⅲ) for seven weeks.The ANAE positive ratios of the peripheral blood T-lymphocytes were much lower in the three zinc toxic groups than that in control group at 7 weeks of age.CD4+ T cell numbers were reduced from 2 to 7 weekds of age in zinc toxic group Ⅲ and from 6 to 7 weeks of age in zinc toxic group Ⅱ,as compared with that of control group.The numbers of CD8+ T cell decreased at 2 and 4 weeks of age in zinc toxic groups Ⅱ and Ⅲ,and at 7 weeks of age in zinc grups Ⅰ and Ⅲ.CD4+/CD8+ ratio was higher at 2 and 4 weeks age,and lower at 6 and 7 weeks of age in zinc toxic groups Ⅰ,Ⅱ and Ⅲ than in control group.The results showed that zinc toxicity would suppress the development of T-lymphocytes and reduce the peripheral blood T-lymphocyte populations.Potential mechanism underlying these observations are also discussed.