Abstract
BACKGROUND AND AIM: The global restriction on antibiotic growth promoters (AGPs) in poultry production due to antimicrobial resistance concerns has accelerated the search for effective, sustainable alternatives. Probiotics derived from agricultural by-products offer a promising strategy to enhance gut health and productivity while reducing environmental waste. Coconut-waste, including coconut water and pulp, is rich in fermentable substrates that support the growth of lactic acid bacteria (LAB) and the production of functional metabolites. This study aimed to perform an integrated in vitro characterization of indigenous microorganisms derived from coconut-waste fermentation as potential probiotic and synbiotic candidates for sustainable poultry production. MATERIALS AND METHODS: Indigenous microorganism solutions (IMOS) were produced through anaerobic fermentation of coconut water and coconut pulp for 5, 10, 15, and 20 days using a completely randomized design with four treatments and five replicates. Physicochemical properties (pH, LAB counts), enzymatic activities (cellulase and mannanase), tolerance to simulated gastrointestinal conditions (acidic pH 2.5, bile salts at 0.3% and 0.5%, and thermal exposure at 42°C), cell surface hydrophobicity, antimicrobial activity against Escherichia coli, Salmonella spp., and Staphylococcus aureus, and short-chain fatty acid (SCFA) production were evaluated using standard microbiological and analytical methods. RESULTS: Fermentation duration significantly influenced all evaluated parameters (p < 0.05). IMOS fermented for 15 days exhibited the lowest pH (3.19 ± 0.02), the highest LAB population (2.05 ± 0.13 × 10¹¹ CFU/mL), optimal cellulase (12.50 ± 0.15 U/mL) and mannanase activities (20.48 ± 0.13 U/mL), and the greatest cell surface hydrophobicity (95.09 ± 0.35%). LAB survival remained high under simulated gastrointestinal stress, reaching 80.23 ± 4.12% at pH 2.5 (6 h), 71.45 ± 0.56% in 0.5% bile salts, and 8.09 ± 0.35 × 10¹¹ CFU/mL at 42°C. Antimicrobial assays demonstrated complete inhibition of E. coli after 24 h at 15 days of fermentation. Acetate (3.34-3.43 g/L) and butyrate (0.66-0.71 g/L) were the dominant SCFAs detected. CONCLUSION: Coconut waste-derived IMOS demonstrates strong in vitro probiotic and synbiotic characteristics and represents a low-cost, environmentally sustainable functional feed additive for poultry. Fermentation for 15 days yielded optimal functional properties. Further in vivo validation is warranted to confirm efficacy under practical production conditions.