Development and assessment of a probiotic supplement for enhancing gut health in broiler chickens

Thesis Abstract

The proliferation of antibiotic-resistant pathogens and increasing consumer demand for antibiotic-free poultry products have underscored the necessity for alternative strategies to promote gut health and enhance performance in broiler chickens. Against this backdrop, this study aimed to develop and rigorously assess a probiotic supplement designed specifically to improve gastrointestinal health, nutrient absorption, and overall production efficiency in broilers. The research objectives included isolating and selecting potent probiotic strains with proven antagonistic activity against common pathogenic bacteria (such as Salmonella spp. and Escherichia coli), formulating a stable probiotic supplement, evaluating its efficacy through controlled feeding trials, and analyzing its impact on gut microflora, intestinal morphology, immune response, and growth performance parameters. The methodology adopted a randomized complete block design involving 300 day-old Ross 308 broiler chicks allocated equally into three treatment groups a control group receiving a basal diet without probiotics, a group fed with a commercial probiotic (positive control), and an experimental group receiving the novel probiotic formulation. The trial spanned 42 days, with data collection at weekly intervals. Key data included growth performance metrics (body weight, feed intake, feed conversion ratio), microbiological analyses of cecal contents (using quantitative PCR and culture methods), histological examination of intestinal villi (via light microscopy), and immune parameters (serum immunoglobulin levels assessed by ELISA). The probiotic strains, primarily Lactobacillus plantarum and Bifidobacterium bifidum, were selected based on in vitro antagonistic activity, acid and bile tolerance, and adhesion properties, following the theoretical framework provided by the Ecological Niche Theory and the Mutualism Model. The probiotic formulations were evaluated for viability and stability under simulated gastrointestinal conditions. Data analysis employed analysis of variance (ANOVA) to identify significant differences among treatment groups with a confidence level set at p<0.05. Regression analyses facilitated understanding correlations between probiotic supplementation and measured health parameters. Microbial diversity indices (Shannon and Simpson) were computed to assess shifts in gut microbiota composition, complemented by Principal Component Analysis (PCA) to visualize microbial community structure changes. The interpretation of results anticipated demonstrating that probiotic supplementation enhances beneficial gut microflora, promotes intestinal villus growth and integrity, modulates immune responses, and subsequently improves growth performance indices. It is expected that the novel probiotic formulation will outperform the commercial standard, offering a cost-effective and sustainable alternative to antibiotics. This study contributes novel insights into probiotic strain efficacy, interactions with host intestinal physiology, and optimal formulation parameters for broilers. It enhances understanding of microbial ecology within the poultry gut and provides empirical evidence supporting probiotic application as a strategic intervention in poultry production systems, aligned with sustainable and antibiotic-free rearing practices. The expected findings advocate for the integration of targeted probiotic supplements into commercial poultry feeding programs, informing policy and industry standards. The primary conclusion underscores that well-formulated probiotics can significantly improve gut health, growth performance, and immune competency in broiler chickens, thus reducing reliance on antibiotics. Recommendations include scaling up probiotic production, conducting longitudinal field trials to evaluate economic benefits, and exploring synergistic effects of probiotic combinations. Future research avenues suggested include genomic analysis of probiotic strains to elucidate mechanisms of action, evaluations under varied environmental conditions, and assessments of probiotic impacts on meat quality and safety. This research aims to substantively advance knowledge in probiotic science within animal nutrition and provide practical solutions for sustainable poultry production.