Bacillus spp. as direct-fed microbial antibiotic alternatives to enhance poultry growth, immunity and intestinal health

Authors: GRANT, ARQUETTE - US Department Of Agriculture (USDA); GAY, CYRIL - US Department Of Agriculture (USDA); Lillehoj, Hyun

Submitted to: Avian Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/5/2018
Publication Date: 5/1/2018
Citation: Grant, A., Gay, C.G., Lillehoj, H.S. 2018. Bacillus spp. as direct-fed microbial antibiotic alternatives to enhance poultry growth, immunity and intestinal health. Avian Pathology. 2:1-13. https://doi.org/10.1080/03079457.2018.1464117.
DOI: https://doi.org/10.1080/03079457.2018.1464117

Interpretive Summary: One of the critical challenges that we face in animal agriculture today is increasing incidence of antimicrobial resistance and superbugs. Although antibiotics was the miracle drug in 1950, misuse and overuse of antibiotics in human and animal medicine fields have led to crisis in antibiotic resistance and many critical infectious microbes are becoming resistant to drugs. Furthermore, there is no new drugs in pipeline and the increasing occurrence of antibiotic-resistant bacteria combined with regulatory pressure and consumer demands for foods produced without antibiotics has caused the agricultural industry to restrict its practice of using antibiotic growth promoters (AGPs) in feed animals. One of solutions for this is developing alternatives to antibiotics. In this report, ARS scientists discuss Bacillus probiotics as an alternative to antibiotics to promote growth and enhance innate immunity of animals. Recent literature indicates that dietary Bacillus probiotics can be an AGP alternative because of their health promoting benefits and ability to survive the harsh manufacturing conditions of feed production. This report provides an overview of several modes of action of Bacillus direct-fed microbials (DFMs) as probiotics as for poultry processors. Appropriate screening and characterization of Bacillus isolates prior to commercialization is necessary to maximize poultry growth to meet the ultimate goal of eliminating AGP usage in animal husbandry.

Technical Abstract: The increasing occurrence of antibiotic-resistant bacteria combined with regulatory pressure and consumer demands for foods produced without antibiotics has caused the agricultural industry to restrict its practice of using antibiotic growth promoters (AGPs) in feed animals. The poultry industry is not immune to this trend, and has been actively seeking natural alternatives to AGPs that will improve the health and growth performance of commercial poultry flocks. Bacillus probiotics have been gaining in popularity in recent years as an AGP alternative because of their health promoting benefits and ability to survive the harsh manufacturing conditions of chicken feed production. This review provides an overview of several modes of action of Bacillus direct-fed microbials (DFMs) as probiotics as for poultry processors. Among the benefits of DFMs are their production of naturally-synthesized antimicrobial peptides (AMPs), gut flora modulation to promote beneficial microbiota along the gastrointestinal track, and various immunological and gut morphological alterations. While these modes of action are not well defined, they promote poultry growth, although growth promotion is not equal across all Bacillus species or within strains. Appropriate screening and characterization of Bacillus isolates prior to commercialization is necessary to maximize poultry growth to meet the ultimate goal of eliminating AGP usage in animal husbandry.