Effects of dietary supplementation of probiotic, Clostridium butyricum, on growth performance, immune response, intestinal barrier function, and digestive enzyme activity in broiler chickens challenged with Escherichia coli K88

Background: Colibacillosis caused by enterotoxigenic Escherichia coli (E. coli) results in economic losses in the poultry industry. Antibiotics are usually used to control colibacillosis, however, E. coli has varying degrees of resistance to different antibiotics. Therefore the use of probiotics is becoming accepted as an alternative to antibiotics. In this study, we evaluated the effects of Clostridium butyricum (C. butyricum) on growth performance, immune response, intestinal barrier function, and digestive enzyme activity in broiler chickens challenged with Escherichia coli (E. coli) K88. Methods: The chickens were randomly divided into four treatment groups for 28 days. Negative control treatment (NC) consisted of birds fed a basal diet without E. coli K88 challenge and positive control treatment (PC) consisted of birds fed a basal diet and challenged with E. coli K88. C. butyricum probiotic treatment (CB) consisted of birds fed a diet containing 2 x 10(7) cfu C. butyricum/kg of diet and challenged with E. coli K88. Colistin sulfate antibiotic treatment (CS) consisted of birds fed a diet containing 20 mg colistin sulfate/kg of diet and challenged with E. coli K88. Results: The body weight (BW) and average day gain (ADG) in the broilers of CB group were higher (P < 0.05) than the broilers in the PC group overall except the ADG in the 14-21 d post-challenge. The birds in CB treatment had higher (P < 0.05) concentration of tumor necrosis factor-alpha (TNF-alpha) at 3 and 7 d post-challenge, and higher (P < 0.05) concentration of interleukin-4 (IL-4) at 14 d post-challenge than those in the PC treatment group. The concentration of serum endotoxin in CB birds was lower (P < 0.05) at 21 d post-challenge, and the concentrations of serum diamine oxidase in CB birds were lower (P < 0.05) at 14 and 21 d post-challenge than in PC birds. Birds in CB treatment group had higher (P < 0.05) jejunum villi height than those in PC, NC, or CS treatment at 7, 14, and 21 d post-challenge. In comparison to PC birds, the CB birds had lower (P < 0.05) jejunum crypt depth during the whole experiment. The birds in CB or CS treatment group had higher (P < 0.05) activities of amylase and protease at 3, 7, and 14 d post-challenge, and higher (P < 0.05) activity of lipase at 3, 7 d post-challenge than PC birds. Conclusions: In all, these results indicate that dietary supplementation with C. butyricum promotes immune response, improves intestinal barrier function, and digestive enzyme activities in broiler chickens challenged with E. coli K88. There is no significant difference between the C. butyricum probiotic treatment and the colistin sulfate antibiotic treatment. Therefore, the C. butyricum probiotic may be an alternative to antibiotic for broiler chickens.