Isolation of kombucha microbes and assessment of their effects on the growth performance immunity and disease resistance of nile tilapia (oreochromis niloticus) | |
| Author | Jeeraporn Foowut |
| Call Number | AIT Thesis no.AQ-25-02 |
| Subject(s) | Tilapia--Diseases Probioics Sustainable aquaculture |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Aquaculture and Aquatic Resources Management |
| Publisher | Asian Institute of Technology |
| Abstract | Kombucha, a mildly sweet and effervescent fermented beverage, is renowned for its health-promoting properties attributed to its diverse microbial community. The aim of the present research was to isolate and characterize microbial species from Thai kombucha and to comprehensively assess their probiotic potential for prospective application in aquaculture systems. Through morphology and 16S and 18S rRNA gene sequencing, five microbial species were identified: three yeasts (Pichia manshurica, Brettanomyces bruxellensis, and Schizosaccharomyces pombe) and two bacteria (Acetobacter tropicalis and Komagataeibacter saccharivorans). In vitro assays demonstrated distinct functional attributes, including proteolytic activity in A. tropicalis and K. saccharivorans, and both proteolytic and amylolytic activities in P. manshurica. Antimicrobial activity was observed in B. bruxellensis against Aeromonas veronii; A. tropicalis against Streptococcus agalactiae serotypes Ia and III; and K. saccharivorans against both pathogens. Stress tolerance assays indicated high pH tolerance (pH 2–10) in B. bruxellensis, while P. manshurica demonstrated notable tolerance to acidic conditions (pH 2–7), bile salts (3%), and NaCl (5%). Based on these characteristics, the isolates were incorporated individually into commercial tilapia feed (10% inclusion rate, 109 CFU/mL) and administered to Nile tilapia (Oreochromis niloticus) fry. Supplementation with A. tropicalis and K. saccharivorans significantly enhanced final weight, daily weight gain, and specific growth rate, reflecting improved growth performance, while feed conversion ratios and survival rates showed favorable, though non-significant, trends. Analysis of immune-related gene expression revealed strain-specific immunomodulatory effects: S. pombe elevated TNF-α, and showed a tendency to increase LYZ and HSP70 expression. B. bruxellensis upregulated LYZ, while K. saccharivorans induced expression of HSP70, suggesting enhanced innate immunity and cellular stress protection. Following experimental challenge with S. agalactiae serotype Ia, fish receiving diets supplemented with A. tropicalis, P. manshurica, and K. saccharivorans exhibited a trend toward improved survival, indicating potential enhancement of disease resistance. Collectively, these findings highlight K. saccharivorans as promising kombucha-derived probiotics capable of improving growth performance, modulating immune responses, and enhancing disease resistance in Nile tilapia, offering potential applications in sustainable aquaculture. |
| Year | 2025 |
| Type | Thesis |
| School | School of Environment, Resources, and Development |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Aquaculture and Aquatic Resources Management (AQ) |
| Chairperson(s) | Ha, Thanh Dong |
| Examination Committee(s) | Salin, Krishna R.;Himanshu, Sushil Kumar |
| Scholarship Donor(s) | Ministry of Agriculture and Cooperatives (MOAC), Thailand;AIT Scholarship |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2025 |