The current study aimed to investigate the effects of Clostridium butyiricum on growth performance, intestinal morphology, serum biochemical response, and immunity in broiler chickens. A total of 330 commercial one-day-old, mixed-sex Ross 308 broilers were randomly divided into five treatment groups with six replicates per group. The broilers were fed the basal diet (CON), the basal diet with 150 mg/kg of aureomycin (AM), the basal diet with C. butyricum at 2 × 108 CFU/kg (CBL), the basal diet with C. butyricum at 4 × 108 CFU/kg (CBM), and the basal diet with C. butyricum at 8 × 108 CFU/kg (CBH). Results showed that the final body weight (BW) (p < 0.01; p < 0.05), ADG from day 22 to 39 (p < 0.05), and ADG from day 1 to 39 (p < 0.01; p < 0.05) were improved in a linear and quadratic response with the inclusion of C. butyricum. There were no differences in feed conversion rate (FCR) among all groups (p > 0.05). Supplementation with C. butyricum quadratically reduced the crypt depth at day 21 (p < 0.01), linearly improved the villus height in the jejunum at day 39 (p < 0.001), and linearly and quadratically increased the villus height to crypt depth (V/C) ratio in the jejunum at day 21 (p < 0.01) and day 39 (p < 0.01; p < 0.001). Dietary C. butyricum affected the thymus index at day 21 and day 39 (linear, p < 0.01), and the bursa of Fabricius index at day 39 (quadratic, p < 0.05). Compared to the AM group, the serum urea contents were decreased (p < 0.05) but the IgG contents were increased in the CBL and CBH groups at day 21 (p < 0.01); in addition, serum albumin (ALB) concentrations in all the C. butyricum-supplemented groups (p < 0.01) and IgG concentrations in the CBM group were augmented at day 39 (p < 0.05). In conclusion, dietary C. butyricum could enhance growth performance by improving jejunal morphology and stimulating immunity organ development in broilers, and could be an alternative to antibiotics in poultry feeds.
Keywords: Clostridium butyiricum; broiler; growth performance; immunity; intestinal morphology; serum biochemical response.