Effects Of Chitosan On Immune Function In Laying Breeders And The Underlying Molecular Mechanism

This study contained three trials.The experiments were conducted to investigate the effects of different concentration of chitosan in diets on immune function and its molecular mechanism in laying breeders.A total of 450 26-week-old healthy Hy-Line brown laying breeders with similar laying rate were randomly allotted to 5 dietary treatments(control group and 4 experimental groups)with 6 replicates in each treatment,and with 15 laying breeders in each replicate.The trial lasted for 56 days.The control group was fed a basal diet without chitosan,the experiment groups were fed the the basal diet supplemented with 250,500,1000,2000 mg/kg chitosan,respectively.The experiment 1 was conducted to discuss the effects of different concentrations of chitosan on immune function in Laying breeders.The experiment 2 was conducted to investigate the effects of chitosan on immune indexes and expression of genes involved in nitric oxide(NO)pathway.The experiment 3 was conducted to investigate the effects of chitosan on IL-1?,IL-2,IL-6,TNF-?,IFN-?,NF-?B content in serum and tissues,as well as their gene expressions of tissues in laying breeders,and to investigate the effects of chitosan on immune function via cytokines and NF-?B pathway and the underlying molecular mechanisms in laying breeders.The results showed as follows:The dietary chitosan improved IgA,IgM,sCD8 in serum of laying breeders in a quadratic dose-dependent relationship.The supplementation of 250,500 mg/kg chitosan improved the concentrations of IgA,IgM,sCD8 in serum.However,the addition of 2000 mg/kg diet was less effective.The dietary chitosan improved NO content in serum,TNOS activity,the relative expression of iNOS in the liver and duodenum of laying breeders in a quadratic dose-dependent relationship.The supplementation of 250.500 mg/kg chitosan in diet improved those parameters.However,the addition of 2000 mg/kg diet was less effective.Dietary supplementation of chitosan significantly increased IL-1?,TNF-?,IFN-? content in the liver and spleen as well as IL-2 and IL-6 content in the liver,spleen and duodenum of laying breeders.The supplementation of 250,500 mg/kg chitosan improved those indices.However,the addition of 2000 mg/kg diet was less effective.The effects of chitosan on the expression of IL-1? in the liver,spleen and duodenum,IL-2 in the spleen and duodenum as well as NF-?B in the liver and spleen of laying breeders in a quadratic dose-dependent relationship.The supplementation of 250,500 mg/kg chitosan improved those indices.However,the addition of 2000 mg/kg diet was less effective.The present results implied that the mechanisms for chitosan to affect immune functions of laying breeders were probably that chitosan activated NF-?B signal pathway as well as expressions of IL-1?,IL-2 and iNOS mRNA,and improved immune active substances.In conclusion,the laying breeders fed a diet containing 250?500mg/kg chitosan had higher immune functions compared with those birds given a control diet.