Effects of Clostridium butyricum on growth performance, immune function, and cecal microflora in broiler chickens challenged with Escherichia coli K88.

This study was conducted to investigate the effects of Clostridium butyricumon growth performance, immune function, and cecal microflora in broiler chickens challenged with Escherichia coli K88. Three hundred sixty 1-d-old broiler chickens were randomly divided into 4 treatments: negative control (NC) birds were fed a basal diet and not challenged with E. coli K88; positive control (PC) birds were fed a basal diet and challenged with E. coli K88; C. butyricum treatment (CB) birds were fed a diet containing 2 × 10(7) cfu C. butyricum/kg of diet and challenged with E. coli K88; and colistin sulfate treatment (CS) birds were fed a diet containing 20 mg of colistin sulfate/kg of diet and challenged with E. coli K88. Birds fed CB had greater (P < 0.05) BW than the PC birds from 3 to 21 d postchallenge. Birds fed CB had greater (P < 0.05) serum IgA and IgY at 14 d postchallenge, greater (P < 0.05) serum IgM at 21 d postchallenge, and greater (P < 0.05) mucosal secreted IgA at 3 and 7 d postchallenge than the PC birds. Birds fed CB had greater concentrations of serum complement component 3 at 14 d postchallenge, and greater (P < 0.05) concentrations of serum complement component 4 at 3, 7, and 14 d postchallenge than the PC birds. Birds in the CS or CB treatments had less cecal E. coli population at 3, 7, and 21 d postchallenge, and less cecal Clostridium perfringens counts at 21 d postchallenge compared with the PC birds. The CB treatment increased (P < 0.05) the population of cecal Lactobacillus at 3 d postchallenge and the number of cecal Bifidobacterium at 3, 14, and 21 d postchallenge in comparison with the PC treatment. The results indicate that dietary supplementation of CB promotes growth performance, improves immune function, and benefits the cecal microflora in Escherichia coli K88-challenged chickens.