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ABSTRACT

Indiscriminate and inappropriate use of antibiotics has led to the emergence of multidrug resistant pathogens, resulting in the ban of the use of antibiotics in animal diets in several countries. As an alternative, probiotics have been under investigation as feed additives to establish an adequate intestinal microflora that improve productive responses in animals. Bacteria from the genus Bacillus are receiving important attention, because of their properties to control enteropathogens and their remarkable capacity to produce endospores. In addition, some Bacillus species have the capacity to synthesize different exogenous enzymes, including protease, phytase, xylanase, keratinase, lipase, and cellulase, that have been reported to improve absorption of nutrients and diminish intestinal viscosity in non-starch polysaccharide rich diets. These benefits make supplementation of Bacillus spores an available and applicable alternative for the use of antibiotic growth promoters, reducing the incidence of various GIT diseases and improving production performance in poultry under commercial conditions. In this review, we summarize the fate, dissemination, and efficacy of Bacillus direct-fed microbial candidates in the gastrointestinal tract of broiler chickens and their effect on health and performance parameters.