Escherichia coli phages isolated from broiler chickens showed ideal characteristics in gut modulation

Phage has gained interest as an alternative antibiotic growth promoter (AGPs) in poultry production. Most phage studies only focus on phages that target pathogens. In this study, we isolated and characterised phages that target non-pathogens from chicken intestines. This study aimed to isolate and characterise phages that target non-pathogenic Escherichia coli for gut modulation study in broiler chickens. Based on a morphological study, the C1 phage belonged to the Podoviridae family, whereas C2, C3, and C4 phages belonged to the Siphoviridae family. The C1, C2, C3, and C4 phages appeared to be unique based on restriction fragment length polymorphisms (RFLPs), amplification of phage signature genes, and protein profiling (SDS-PAGE). The C1 phage had an ideal multiplicity of infection (MOI) of 0.001, followed by 0.1 for the C2, C3, and C4 phages. C1 had the highest adsorption rate of 99.7% in 1 min, followed by C2 (98%), C3 (98.7%), and C4 (98.2%), all of which were within 2 min. C1 also exhibited the largest burst size (72 PFU/infected cell) and the shortest latent period (5 min). The latent period of the C2, C3, and C4 phages was longer, lasting 10 minutes, and their burst sizes were 70, 77, and 46 PFU/infected cells, respectively. All phages had optimum lytic activity at pH 7 and 37°C. Each phage was unique and possessed favourable lytic characteristics, making all of them suitable for gut modulation study in chickens.