Protective Mechanism Of Baicalin-copper Complex On Intestinal Injury Caused By Escherichia Coli In Chicks

Avian escherichia coli(E.coli)is a.kind of local or systemic infectious disease caused by pathogenic E.coli.At present,the prevention and treatment of avian E.coh mainly depends on the addition of antibiotics.However,at present:"green" breeding and"forbidden resistance" breeding have become inevitable in the industry.Therefore,how to effectively prevent and control avian E.coli has become one of the key issues of the current breeding industry.However,the effects of baicalin-copper complex,a metal complex ofbaicalin,on intestinal inflamm ation in chicks are still unknown.To observe the effects of different doses of baicalin-copper complex(10 mg/kg:20 mg/kg and 40 mg/kg)on diarrhea rate,mortality rate,ileum antioxidant enzyme activity,oxidative stress and inflammatory factor mRNA and ileum PI3K/AKT/NF-κB protein expression The results provide a theoretical basis for the application of baicalin-copper complex in the prevention and control of avian E.coli disease.The results are as follows:1.Compared with the control group,diarrhea rate and mortality rate of chickens in E.coli group were 73.33%and 53.33%:respectively;The diarrhea rate and mortality of laying hens in baicalin-copper complex group were significantly decreased,and the diarrhea rate and mortality of laying hens in baicalin-copper complex 40 mg/kg group were 26.67%and 6.67%respectively.It is suggested that baicalin-copper complex has control effect.2.Compared with the control group,the ileum of chickens in E.coli group showed crypt hyperplasia,intestinal villus atrophy,inflamm atory cell infiltration and bleeding;The degree of ileum lesion was significantly reduced in baicalin-copper complex group.3.Compared with the E.Coli group,the activities of antioxidant enzymes GSH-Px,SOD and CAT in ileum of chickens in E.coli group were signiicantly decreased,while the content of MDA was significantly increased(P<0.05);The activities of antioxidant indexes GSH-Px,SOD and CAT in ileum of 10 mg/kg,20 mg/kg and 40 mg/kg baicalin-copper complex groups were increased,while the content of MDA was decreased:and the differences were significant(P<0.05).4.Compared with the E.coli group,the mRNA expressions of antioxidant signaling genes Nrf2,HO-1,CAT,SOD-1 and GCLM in ileum of chickens in E.coli group were significantly decreased(P<0.05);The mRNA expressions of Nrf2,HO-1,CAT,SOD-1 and GCLM genes in ileum of chicks fed 10 mg/kg,20 mg/kg and 40 mg/kg baicalin-copper complex groups were significantly increased(P<0.05).5.Compared with the E.coli group,the mRNA expressions of TNF-α,IL-6,EL-1βand IL-8 of ileum inflammation genes in chickens in E.coli group were increased;The mRNA expression of TGF-β and IL-10 were decreased:and the difference was significant((P<0.05).The mRNA expressions of TNT-α,IL-6,IL-1β and IL-8 in ileum of 10 mg/kg,20 mg/kg and 40 mg/kg baicalin copper laying hens were decreased,and the differences were significant(P<0.05).The mRNA expression of TGF-β and IL-10 increased significantly(P<0.05).6.Compared with the E.coli group,the mRNA expressions of ileum barrier proteins Claudin-1,Claudin-3,Occludin,ZO-1,ZO-2 and MUC were decreased in e.coli group,and the differences were significant(P<0.05).The mRNA expressions of claudin-1,Claudin-3,Occludin,ZO-1,ZO-2 and MUC genes in ileum of chicks in 10 mg/kg,20 mg/kg and 40 mg/kg baicalin-copper complex groups were increased,and the differences were significant(P<0.05).7.Compared with the E.coli group,P-AKT/AKT in ileum of chickens in E.coli group were decreased,and P-NF-κB/NF-κB were increased,with significant differences(P<0.05).The ileum P-AKT/AKT levels were increased and p-NF-κB/NF-κB was decreased in 10 mg/kg,20 mg/kg and 40 mg/kg baicalin-copper complex groups,the differences were significant(P<0.05).Conclusion:Baicalin-copper complex can significantly relieve ileum inflammation and injury caused by E.coli in chickens,which may be related to PI3K/AKT/NF-κB signaling pathway,so it has application value.