| Objective: To investigate the effects of Lactobacillus acidophilus on the distribution of intestinal glial cells and the secretion of immune factors IL-1beta,IL-2 and IFN-gamma by intestinal EGC in broilers infected with Escherichia coli,and to investigate the effects of Lactobacillus acidophilus on the number and distribution of intestinal glial cells in Broilers and the EGC score of broilers infected with Escherichia coli.The effects of secreted immune factors can provide references,and provide scientific basis for chicken feeding,disease prevention and treatment.Methods: 160 healthy yellow-feathered broilers from 1 day old were divided into 4 groups and control group(CG)fed with basic diet;the first group was fed with only add 4% of the daily dietary amount of chicken,Lactobacillus acidophilus powder(LA),and the broilers were fed with basic diet;the second group was fed with broilers exposed to Escherichia coli(EC)and fed with Escherichia coli above 10~8 CFU;the third group was fed with 4% Lactobacillus acidophilus(EC+LA)supplemented by Ecoli,and the broilers were fed with bacteria above 10~8 CFU.From 7 days old,yellow-feathered broilers in the attack group were inoculated with E.coli O1 strain(15 *10~8 CFU/chicken)in drinking water for 3 days.Tissue samples were taken immediately after slaughter of chickens with clinical symptoms,and some were fixed in Helly solution for modified Holzer staining;the others were placed in 4% polyformaldehyde solution for immunohistochemical test.The two groups were sampled in the same way.Result: 1.The distribution and quantity of EGCs were observed by modified Holzer staining.The EGCs in the experimental group were mainly distributed in the lamina propria and submucosa of the intestinal mucosa.The mucosal muscle layer was only distributed in a small amount,and the EGCs in the lamina propria of the intestinal villi were aggregated.The number of EGCs in the intestinal tract of the experimental group was significantly higher than that of the control group(P<0.05),and the difference of EGCs between the experimental groups was not significant(P>0.05).EGCs in the control group were widely distributed in the intestinal mucosa,submucosa and muscle layers of the chicken,and the parts were scattered.2.Immunohistochemistry and ELISA showed that the expression of IL-1? in the intestinal tract of E.coli model group increased significantly with the increase of chicken age(P<0.05),and IL-1? was concentrated in the mucosal epithelium and lamina propria.The distribution of IL-2 in the lamina propria is concentrated,followed by the submucosa and muscle layers.In the pathogenic E.coli invaded the chicken intestine,IL-2 aggregated in the mucosal epithelium,lamina propria and submucosal plexus.3.Immunohistochemistry and ELISA showed that IFN-? was expressed in the mucosal epithelium,lamina propria and muscle layer of chicken intestinal mucosa.In the LA group,theintestinal tract IFN-? was weakly expressed;in the E.coli challenge group,IFN-? was expressed in the mucosal epithelium and lamina propria,and the submucosa and muscle layer were weakly expressed.With the increase of chicken age,the expression of IFN-? in the intestinal tract of LA group was significantly increased by E.coli challenge(P<0.05).Conclusion: Adding 4% Lactobacillus acidophilus to the diet can significantly increase the number of EGCs in the intestine of the broiler;the IL-1? concentration in the intestinal tract of the LA group is lower than that of the other groups(P<0.05),and IL-1? in the intestinal tract of the E.coli infected group.The concentrations of IL-2 and IFN-? were higher than those of the uninfected group(P<0.05),indicating that E.coli increased the concentration of inflammatory immune factors.The addition of LA increased the concentration of IFN-? in the intestinal mucosa,and the difference was significant(P<0.05),Lactobacillus acidophilus plays an immunopotentiating role in the pathogenic E.coli infection of chickens. |
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