LAUSR

AIMS Sub-therapeutic use of antibiotics as a growth promoter in animal diets has either been banned or voluntarily withdrawn from use in many countries to help curb the emergence of antibiotic-resistant pathogens. Probiotics may be an alternative to antibiotics as a growth promoter. We investigated the effects of a novel probiotic strain Bacillus amyloliquefaciens H57 (H57) on the performance and microbiome-associated metabolic potential. METHODS AND RESULTS Broiler chickens were fed either sorghum- or wheat-based diets supplemented with the probiotic H57. The growth rate, feed intake and feed conversion in supplemented birds were compared with those in non-supplemented control. Caecal microbial metabolic functions were studied with shotgun metagenomic sequencing. H57 supplementation significantly increased the growth rate and daily feed intake of meat chickens relative to the non-supplemented controls without any effect on feed conversion ratio. In addition, relative to the non-supplemented controls, gene-centric metagenomics revealed that H57 significantly altered the functional capacity of the caecal microbiome, with amino acid and vitamin synthesis pathways being positively associated with H57 supplementation. CONCLUSIONS Bacillus amyloliquefaciens H57 improves the performance of meat chickens or broilers and significantly modifies the functional potential of their caecal microbiomes, with enhanced potential capacity for amino acid and vitamin biosynthesis.A feed supplement like H57, with the ability to enhance weight gain through modulation of intestinal microbial functions, has the potential to be an alternative to antibiotic growth promoters and provide substantial benefits to the poultry industry.