Whole genome sequence analysis of Bacillus amyloliquefaciens strain S2.5 as a potential probiotic for feed supplement in livestock production.

Background: Supplementing probiotics in livestock feed is increasing due to concerns over the potential harm caused by antibiotics and other chemical growth promoters. Several Bacillus sp. have been used as probiotic supplements for livestock. In this study, Bacillus amyloliquefaciens S2.5 was isolated from freshwater and its potential probiotic characteristics were evaluated in vitro. The whole genome of strain S2.5 was sequenced, and its probiotic traits were annotated using bioinformatic tools.

Results: Both vegetative cells and spores of strain S2.5 remained stable throughout the 1.5 h of gastric juice and 48 h of intestine simulation. The strain S2.5 harbored the ability to produce glucoamylase, carboxymethyl cellulase, protease, and chitinase. It is also susceptible to all six tested antibiotics. The complete genome sequence shows genes related to acid-bile tolerance, environmental stress resistance, hydrolases, and adhesion to gut mucosa, confirming probiotic traits in the in vitro experiments.

Conclusions: B. amyloliquefaciens S2.5 demonstrated potential probiotic characteristics and its genetic profile in the in vitro experiments. Further in vivo assessments of B. amyloliquefaciens S2.5 on livestock and poultry should be performed to assess its practical application.