Effect of Bacteriophage and Synbiotic on Multidrug Resistant Salmonella Experimentally Infected Broiler Chicken

Abstract

ANTIBIOTIC resistance in Salmonella species poses significant challenges in poultry production, necessitating the exploration of alternative therapeutic approaches. This study investigated the efficacy of bacteriophage and synbiotic as potential alternatives to conventional antibiotics in treating Salmonella infections in broiler chickens. Samples from the liver, cecum, and spleen of one hundred diseased broiler chickens were collected for Salmonella isolation, identification, and serotyping. The isolation rate of Salmonella was found to be 5%. The isolated strain demonstrated complete resistance to multiple antibiotics, with PCR analysis confirming the presence of resistance genes blaTEM (100%), qnrA (100%), and blaCTXM (80%). Bacteriophages were isolated from sewage samples using identified S. enteritidis strains. A controlled trial was conducted using specific pathogen-free (SPF) chicks (n=120) divided into six groups: negative control (G1), positive control (G2), bacteriophage-treated (G3), synbiotic-treated (G4), bacteriophage-synbiotic combination (G5), and doxycycline-treated (G6). Treatment efficacy was evaluated through bacterial enumeration, oxidative stress markers (MDA, GSH, SOD), immune parameters (total protein, albumin, globulin, IgM, IgG), and growth performance metrics. The bacteriophage-synbiotic combination demonstrated superior efficacy in reducing S. enteritidis colonization (p<0.05) while enhancing beneficial Lactobacillus populations. All treatment modalities significantly improved antioxidant status and immune responses compared to untreated controls, with doxycycline showing superior immunomodulatory effects. Growth parameters, including body weight, weight gain and feed conversion ratio (FCR), improved significantly across treatment groups, particularly with the combination therapy. These findings suggest that bacteriophage-synbiotic combination represent a promising alternative to conventional antibiotics in managing Salmonella infections in poultry production systems.