Effect of Bacillus subtilis PB6 (CloSTAT) on Broilers Infected with a Pathogenic Strain of Escherichia coli
Journal of Applied Poultry Research
In an attempt to demonstrate the efficacy of Bacillus subtilis PB6, isolated from the gut of a healthy chicken, on broiler performance, an experimental trial was conducted in which broilers, infected or uninfected with a pathogenic strain of Escherichia coli, were supplemented with B. subtilis PB6 (CloSTAT) or zinc bacitracin-colistin sulfate and compared against negative controls given no antibiotic supplementation. We observed 10-and 8-point improvements in feed conversion ratio (FCR) in
... old uninfected broilers treated with B. subtilis PB6 when compared with the negative and antibiotic controls, respectively. However, infected birds supplemented with B. subtilis PB6 registered a significant 15-point FCR improvement over those in the negative control group (P < 0.05). Compared with the negative control, the increase in body weights of uninfected and infected 42-d-old broilers receiving B. subtilis PB6 were 97 and 152 g, respectively (P < 0.05). The growth-promoting and protective results from this study indicated that B. subtilis PB6 not only helped in the maintenance of beneficial bacteria but also could act as a replacement for antimicrobial growth promoters in broilers. The percentages of mortality of infected birds within antibiotictreated groups and B. subtilis PB6-treated groups were reduced from 14% to 6 and 8%, respectively. Numerically, uninfected birds supplemented with B. subtilis PB6 had elevated levels of lactobacilli (1.4 to 4.5 × 10 7 cfu/g) in their intestinal tracts (32-and 42-d-old broilers) compared with the controls. Even after being challenged with a pathogenic strain of E. coli, the lactobacilli counts in the B. subtilis PB6-treated birds tended to remain the same as those receiving antibiotic and were considerably higher than those of the untreated birds.