拟杆菌早期干预对大肠杆菌攻毒雏鸡肠道健康的影响OA

[Objective]This study aimed to investigate the alleviating effects of early intervention with Bacteroides on intestinal health in chickens challenged with Escherichia coli(E.coli),providing new insights for sustainable and healthy poultry farming.[Method]A total of 150 newly hatched healthy arbor acres(AA)male chicks were randomly divided into three groups:(1)Control group(gavaged daily with 0.5 mL physiological saline from day 1 to day 8);(2)E.coli group(gavaged daily with 0.5 mL physiological saline from day 1 to day 7,followed by a challenge with 0.5 mL avian pathogenic E.coli suspension on day 8);and(3)Bacteroides group(gavaged daily with 0.5 mL Bacteroides sus-pension from day 1 to day 7,followed by a challenge with 0.5 mL avian pathogenic E.coli suspension on day 8).At 3 days(10 days of age)and 14 days(21 days of age)post-challenge,8 chickens per group were randomly selected for slaughter and sampling.Growth performance,serum biochemical and antioxidant indices,serum inflammatory cytokines,intestinal morphology,expression of intestinal barrier-related genes,and gut microbiota composition were analyzed.[Result]Early intervention with Bacteroides showed no significant effects on growth performance or immune organ indices in E.coli challenged chickens.However,it significantly enhanced total antioxidant capacity and serum supero-xide dismutase activity,improved serum inflammatory cytokine levels.The relative mRNA expression levels of OCLN,CLDN3,ZO1,and ZO2 in the jejunum,as well as CLDN3,ZO1,and ZO2 in the ileum,were significantly upregulated on day 3 post-challenge.On day 14 post-challenge,the relative mRNA expression levels of OCLN,CLDN3,ZO1,and ZO2 in both the jejunum and ileum were sig-nificantly increased.Additionally,Bacteroides intervention altered cecal microbiota composition,increasing the relative abundance of Bacteroides and reducing Escherichia_Shigella abundance.[Conclusion]Early intervention with Bacteroides significantly improved immune regulation in E.coli challenged chickens and reshaped gut microbiota colonization patterns,effectively alleviating pathogen-induced physiological damage.