Effect of Dietary Synbiotic as a Replacement for Antibiotics on the Growth Performance, Gut Health and Immune Response in Broiler Chickens

This study examined the impact of dietary supplementation with a synbiotic on the growth performance, carcass traits, blood biochemical profile, gut microbiome, gut morphology, and immune response of broiler chickens. A total of 162 day-old VenCobb-400 broiler chicks were randomly divided into three dietary groups, each with six replicated pens (n = 6), housing nine broiler chickens: 1) basal diet without any growth promoter (CON), 2) basal diet with antibiotic (Bacitracin methylene disalicylate -BMD) at 500g/ton feed (AGP), and 3) basal diet with synbiotic (Lactobacillus rhamnosus NCDC 298 + fructo oligosaccharide) at 1 ml/bird in drinking water (SYN). Body weight, feed intake, and feed conversion ratios (FCR) were monitored weekly for 42 days. Blood biochemistry was assessed on day 28, and immune response was evaluated on days 28 and 35. Carcass traits, gut microbiome, and gut morphology were examined at the end of the trial. The SYN group exhibited significantly higher final body weight and average daily gain compared to the CON and AGP groups. Feed conversion ratio was improved in the SYN and AGP groups compared to the CON group. Total Escherichia coli and Salmonella counts were significantly lower in the SYN group, while Lactobacillus counts were significantly higher. In conclusion, synbiotic supplementation could serve as a promising alternative to antimicrobials in broiler production, demonstrating beneficial effects in broilers fed an antibiotic-free diet.