Complementary potential of bacteriophages and synbiotics as an alternative to antibiotic growth promoters in poultry production

ABSTRACT Antibiotic growth promoters ( AGP ) have historically been used in conventional animal feeds to enhance feed efficiency, prevent diseases and increase the production of animal-derived foods. However, the misuse of AGP has led to the emergence of multi-drug resistant pathogenic bacteria and the discovery of antibiotic residues in animal products, posing severe health risks to the environment, humans and animals. Alternatively, bacteriophages and synbiotics can be used as promising candidates to maintain poultry production and ensure food safety. Bacteriophages have high specificity against pathogens, allowing the proliferation of beneficial gut microbes to enhance gut health, without leaving any harmful residues. Similarly, synbiotics, a combination of prebiotics and probiotics, enhance gastrointestinal function, and nutrient absorption, stimulate immune responses and improve stress resilience and performance. However, there are limited studies that have explored their complementary application in poultry production. Thus, this review explored 152 studies published between 2016 and 2025, to ensure the inclusion of methodologically up-to-date research. The published studies were identified through Google Scholar, Web of Science, PubMed, Wiley, Taylor & Francis, ScienceDirect, and Scopus, following the PRISMA procedure. The methodology included predefined inclusion and exclusion criteria, database specific searches, duplicate removal and stepwise screening of titles, abstracts and full texts. The review indicated that there are knowledge gaps on in vivo validation and industry application of bacteriophage-synbiotic application as potential alternatives to AGP. However, from their individual effectiveness, it can be deduced that their complementary application could offer a promising strategy to improve efficiency and product quality, reduce economic losses, and support antibiotic-free production systems. Thus, in vivo validation, standardization and commercial-scale studies are required to confirm their synergistic effects and large-scale applicability in poultry.