Effects Of High Level Of Copper On Nf-κB Signal Pathway And Inflammatory Factors In Immune Organs Of Broilers

Copper is one of the essential trace elements in organisms,and involved in numerous metabolic process.However,the excess intake of copper will induces copper poisoning.It has reported that high levels of copper would result in the damage of the immune function of animals,but the study of high-copper on inflammatory factors and NF-κB signal pathway in poultry is rare.In this study,the broilers were fed with different concentration of copper in the basal diet,the expression of NF-κB signal pathway and the related inflammatory factors of immune organs of broilers were examinated,which provided theoretical basis for further study on the pathological changes of broilers fed with high-copper diets.Two hundred and fourty one-day-old AA broiler chickens were randomly divided into 4 groups with 60 birds in each group.Copper sulfate was selected as the experimental copper source.The copper levels of the basal diet of control group was 11mg/kg,which was recommended by NRC(2012),and the copper levels in the three experimental groups of was 110 mg/kg(high-copper group I),220 mg/kg(high-copper group II),330 mg/kg(high-copper group III),respectively.The period of experiments lasted 7 weeks.The structure and pathological changes of spleen,thymus and Bursa of Fabricius were observed by optics microscope.The m RNA expression levels of genes(NF-κB,TNF-α,IL-1β,IL-1,IFN-γ,COX-2,i NOS and IL-2)were measured by real-time quantitative polymerase chain reaction(RT-q PCR).The protein content of NF-κB,TNF-α,IL-1β and IL-1 were measured by Enzyme-linked immunosorbent assay(ELISA).The protein expression of NF-κB,TNF-α and IFN-γ were detected by Western-Blot(WB).The results showed that high-copper could induce the change of the structure of broilers spleen,thymus and Bursa of Fabricius: the lymphatic sheath around splenic artery became thicker,the splenic corpuscles increased;the ratio of thymic cortex to medulla increased,thymus corpuscles increased,the ratio of area and width of Bursa nodule cortex and medulla increased.The levels of the m RNA expression of inflammatory related genes(TNF-α,IL-1β,IL-1,IFN-γ,COX-2,i NOS,IL-2)were increased,as well as the NF-κB signal pathway induced by high-copper;the protein expression levels of inflammatory related factors(NF-κB,TNF-αand IFN-γ)were increased;The content of the protein(NF-κB,TNF-α,IL-1β and IL-1)of spleen,thymus and Bursa of Fabricius were increased by high-copper.These results suggest that the expression of NF-κB signal pathway and the related inflammatory factors may incresed by high-copper in the broilers.