Effect Of Dietary High Fluorine On Immune Organs In Chickens

Three hundred one-day-old avian broilers were divided into four groups and fed on control diet(F 23.00mg/kg) and High fluorine diets(F 400.00mg/kg,High fluorine groupâ… ; F 800.00mg/kg,High fluorine groupâ…¡;F 1200.00mg/kg,High fluorine groupâ…¢) for 42 days.The experiment was conducted with the objective of examining the impact of high fluorine on immune organs in chickens by methods of experimental pathology and flow cytometry(FCM).Results as follow:Spleen:No obvious changes were observed in high fluorine groupâ… .Histopathologically, the population of lymphocytes were greatly decreased in high fluorine groupsâ…¡andâ…¢. Ultrastructurally,apoptotic lymphocytes were obviously increased with swelled mitochondria and enlarged endoplasmic reticulum in high fluorine groupsâ…¡andâ…¢.As measured by flow cytometry,lymphocytes in G₀/G₁ phase were significantly increased while lymphocytes in S phase,G₂+M phase and Proliferating index(PI) value were obviously decreased in high fluorine groupsâ…¡andâ…¢.At the same time,the percentage of apoptotic splenocytes was significantly increased in high fluorine groupsâ…¡andâ…¢when compared with that of control group.Moreover,immunohistochemistry tests showed increased frequencies of positive cells in Bax detection,and decreased Bcl-2 protein in high fluorine groupsâ…¡andâ…¢.Thymus:Lymphocytes in the medulla were decreasing with the increase days of age in high fluorine groupâ… .At the same time,the population of lymphocytes in both cortex and medulla were greatly decreased in high fluorine groupsâ…¡andâ…¢.As measured by flow cytometry,lymphocytes in G₀/G₁ phase were increased while lymphocytes in S phase, G₂+M phase and PI value were decreased in high fluorine groupâ… from 28 days of age to 42 days of age.However,lymphocytes in G₀/G₁ phase were significantly increased while lymphocytes in S phase,G₂+M phase and PI value were obviously decreased in high fluorine groupsâ…¡andâ…¢from 14 days of age to 42 days of age.Meanwhile,the percentage of apoptotic splenocytes was significantly increased in the three high fluorine groups when compared with that of control group,which was consistent with the results of ultrastructral observation and Bax/Bcl-2 tests.Moreover,peripheral blood T-cell subsets tests showed that the percentages of CD₄⁺ and CD₈⁺ T cells were decreased in the three high fluorine groups when compared with those of control group.Meanwhile,the CD₄⁺/CD₈⁺ ratio were lower in high fluorine groupâ…¡at 28 days of age and in high fluorine groupâ…¢at 42 days of age than in control group.Also,the serum IL-2 contents were lower in the three high fluorine groups than in control group.Bursa of Fabricius:No obvious changes were observed in high fluorine groupâ… . Histopathologically,lymphocytes were decreaed at 14 days of age,then increased at 28 days of age,and finally decreased at 42 days of age in high fluorine groupsâ…¡andâ…¢.As measured by flow cytometry,lymphocytes in G₀/G₁ phase were decreased while lymphocytes in S phase,G₂+M phase and PI value were increased in high fluorine groupsâ…¡andâ…¢at 28 days of age.However,lymphocytes in G₀/G₁ phase were significantly increased while lymphocytes in S phase,G₂+M phase and PI value were decreased at 14 days of age and 42 days of age.Meanwhile,the percentage of apoptotic splenocytes was highest at 28 days of age and was consistent with ultrastructral observation and Bax/Bcl-2 tests.Moreover,the contents of serum IgG and IgM were decreased while the content of serum IgA was increased in high fluorine groupsâ…¡andâ…¢when compared with those of control group.Conclusionâ‘ It was concluded that 400mg/kg dietary high fluorine intake markedly decreased percentages of the peripheral blood T-cell subsets and influenced the biological function of mature T lymphocytes,which showed the inhibition of cellular immune function.â‘¡It was concluded that 800mg/kg～1200mg/kg dietary high fluorine intake reduced the contens of serum IgG and IgM with increased serum IgA contents,which would lead to further impact on humoral immune function.â‘¢It was concluded that 400mg/kg dietary high fluorine intake greatly inhibited the cellular immune function,but had no obvious influence on the humoral immune function in chickens.The tolerance of immune organs on dietary high fluorine in chickens shows as follow:Bursa of Fabricius＞Spleen＞Thymusâ‘£It was concluded that 800mg/kg～1200mg/kg dietary high fluorine intake obviously decreased the activities of antioxidase(SOD,GSH-Px) and increased products of lipid peroxidation(MDA),which caused oxidative damage in spleen.⑤It was concluded that 800mg/kg～1200mg/kg dietary high fluorine intake inhibited the proliferation and development of lymphocytes in immune organs(Bursa of Fabricius, spleen and thymus) and increased the population of apoptotic lymphocytes,which finally led to inhibition on the development of immune organs and impaired the immune function in chickens.