Effects of Lactobacillus acidophiluson the growth performance, immune response, and intestinal barrier function of broiler chickens challenged with Escherichia coliO157

We studied the effects of Lactobacillus acidophilus(L. acidophilus) on the growth performance, intestinal morphology, barrier function, and immune response of broilers challenged with Escherichia coliO157 (E. Coli). A total of 360 1-day-old Cobb male broilers were tested in a 3 × 2 factorial arrangement with 3 dietary L. acidophiluslevels (0, 5 × 108CFU/kg, and 10 × 108CFU/kg of diet) and 2 disease challenge treatments (control or E. colichallenged). Results showed that E. colichallenge decreased the ADG, ADFI, and BW of broilers from 15 to 21 d (P< 0.05), increased the jejunum intestinal wall thickness, and significantly increased the mortality rate. E. colichallenge significantly (P< 0.05) decreased the serum IgA and IgM contents and peripheral blood CD3+ T cell counts (P< 0.05), increased the serum CRP, DAO, and LPS levels at 21 d; upregulated the mRNA expression of iNOS, IL-8, IL-1β in the jejunum and iNOS in the spleen, and downregulated the occludin and ZO-1 mRNA expression in the ileum at 21 d compared with uninfected birds (P< 0.05). Dietary L. acidophilussupplementation consistently showed higher BW, ADG, ADFI, and jejunum and ileum V:C ratio at 14 d and 21 d in the presence and absence of E. colichallenge (P< 0.05). L. acidophilussupplementation reduced the mortality rate caused by E. colichallenge (P< 0.05), decreased the serum CRP, DAO, and LPS levels at 14 d and 21 d; upregulated the mRNA expression of occludin and ZO-1 in the jejunum and ileum, and downregulated the mRNA expression of iNOS, IL-8, and IL-1β in the jejunum in E. colichallenged birds at 21 d (P< 0.05). Dietary supplementation with L. acidophiluscan improve the growth performance, intestinal health, and survival of broilers challenged with E. coli.