Advances in probiotic research for aquaculture: screening methods, mechanisms, and regulatory considerations

Abstract

Aquaculture’s swift rise to prominence as the world’s main source of animal protein has created problems with disease outbreaks, antibiotic resistance, declining water quality, and degradation in environmental sustainability. Probiotic strains such as Bacillus, Lactobacillus, Enterococcus, and Pseudomonas exhibit notable capability to enhance stress tolerance, immunity, host growth, and reproductive efficiency. Critical evaluation parameters to guarantee safety and effectiveness, including hemolysis assays, antibiotic susceptibility testing, bile and pH tolerance, adhesion and colonization ability and pathogen antagonism. The paper emphasizes how probiotics improve hematological indices, antioxidant status, feed utilization, digestive enzyme function, and resistance to common fish infections like Aeromonas. Probiotics also help to improve water quality by reducing hydrogen sulfide and ammonia, cycling nitrogen, and lowering chemical and biological oxygen demands. Despite encouraging results, various issues with strain standardization, long-term biosafety evaluation, horizontal gene transfer tracking, and species dosage optimization were noticed.