Vet Med - Czech, 2026, 71(2):35-53 | DOI: 10.17221/5/2025-VETMED

Effect of bacteriophages on growth performance and health indicators in broiler chickens in the absence of bacterial challenge – A reviewReview

MA Mohd Shaufi¹, SL Chia², H Abu Hassim³, MT Yusof¹, MA Akbar¹, AAL Song¹, S Mustafa¹

¹ Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, University of Putra Malaysia, Serdang, Selangor, Malaysia

² Research Laboratory of Probiotics and Cancer Therapeutics, UPM-MAKNA Cancer Research Laboratory (CANRES), Institute of Bioscience, University of Putra Malaysia, Serdang, Selangor, Malaysia

³ Institute of Tropical Agriculture and Food Security, University of Putra Malaysia, Serdang, Selangor, Malaysia

This review examines bacteriophages as alternatives to antibiotic growth promoters (AGPs) in broiler chickens, with a unique focus on effects observed in studies without experimental bacterial challenges. Driven by global antimicrobial resistance (AMR) concerns and sustainable poultry production demands, phage supplementation, a targeted strategy, potentially improves growth performance and gut health by preserving beneficial microbiota. This literature analysis assesses phage efficacy in healthy broilers under non-challenge conditions, evaluating key variables such as phage concentration, delivery, and targets, as well as outcomes such as feed conversion ratio (FCR) and gut health markers. Crucially, this review extends beyond efficacy to explore phage immunomodulatory capabilities, outlines optimisation strategies, and addresses risks and mitigation. Key findings show mixed efficacy of phages in non-challenged broilers: significant improvements in FCR and gut health were generally observed with high phage concentrations (e.g., ≥10⁸ PFU/g) and continuous delivery protocols, whereas lower doses yielded inconsistent or minimal benefits. Furthermore, choosing which bacteria phages target – for example, aiming at pathogens like Salmonella or managing common gut bacteria such as E. coli – greatly impacts outcomes. While phages show considerable potential as AGP alternatives, the review highlights that further research is vital to resolve inconsistencies, standardise protocols, and understand host genetic and environmental influences to optimise their commercial application.

Keywords: antibiotic alternatives; feed efficiency; gut microbiota; phage formulation; poultry health

Received: January 20, 2025; Revised: June 3, 2025; Accepted: July 15, 2025; Published: February 27, 2026  Show citation