Assessment of the potential of the multi-enzyme producer Bacillus amyloliquefaciens US573 as alternative feed additive.

BACKGROUND: Recently, probiotics have increasingly been used as feed additives in poultry diets as an alternative to antibiotic growth promoters fostering resistance development. RESULTS: This study was aimed at assessing the potential of Bacillus amyloliquefaciens US573 as a direct-fed microbial. The US573 strain was found to be free of harmful enzymatic activities and sensitive to antibiotics. In addition, it showed a good acid and bovine bile tolerance, high adhesion efficacy to chicken enterocytes, and an ability to form biofilms, which may favor its survival and persistence in the animal gastrointestinal tract. Moreover, besides the previously described extremely salt-tolerant and highly thermostable phytase, the US573 strain secretes xylanase, ß-glucanase and amylase activities useful in neutralizing antinutritional factors and maximizing the absorption of nutrients. The secretion of such enzymes may be responsible for the good performance of the US573 isolate in the digestibility of wheat in vitro. Indeed, using the vegetative cells, a yield of wheat dry matter digestibility of approximately 48% was achieved, which is slightly lower than the commercial feed additive Rovabio used as a reference (56.73% digestibility). CONCLUSION: The obtained results illustrate the potential of US573 strain as a promising direct-fed microbial candidate for application in the poultry industry. © 2017 Society of Chemical Industry.