Humoral immune response and protection of monovalent and bivalent streptococcus agalactiae serotype IA and III vaccines in Nile tilapia, Oreochromis Niloticus fry | |
| Author | Kolvankar, Vaishnavi Manoj |
| Call Number | AIT Thesis no.AQ-24-04 |
| Subject(s) | Bacterial diseases in fishes Fishes--Diseases--Prevention Fishes--Vaccination Tilapia |
| 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 | This study addresses the issue of Streptococcus agalactiae infections in tilapia aquaculture, specifically focusing on the threat posed by serotypes Ia and III, which result in substantial economic losses and elevated mortality rates. Despite the development of vaccines, there remains a critical need to thoroughly evaluate their efficacy, particularly concerning fry immunity and protection against specific serotypes. The study investigates the humoral immune response, specifically IgM antibody production, in tilapia fry following immersion immunization with monovalent and bivalent vaccines targeting S. agalactiae serotype Ia and III, ultimately aiming to enhance vaccine-based disease control. The working procedure involves control groups receiving no vaccine, while experimental groups are subjected to immersion in monovalent or bivalent vaccines, followed by an oral boost with respective vaccines mixing with pellet feed at day 21-25 post immunization. Efficacy of vaccines were evaluated by experimental challenge with S. agalactiae serotype Ia and III at day 35 post vaccination. Samples collected weekly post-immunization and antibody response is determined using ELISA assays on. Results reveal that vaccinated groups exhibit significantly higher antibody titers compared to non-vaccinated counterparts, with peak levels observed on days 14 and 28 post-vaccination. Notably, recipients of the monovalent vaccine demonstrate a superior antibody response compared to those given the bivalent vaccine, attributed to antigen competition. Furthermore, the experimental challenge test carried out on day 35 after immunization showcased the protective effectiveness of the vaccines. Monovalent vaccinated groups displayed a RPS of 62.07% against serotype Ia and 67.86% against serotype III, indicating increased resistance to S. agalactiae infection in comparison with the control group. Meanwhile, in the bivalent vaccinated groups, the RPS stood at 55.17% and 46.43% when challenged with serotypes Ia and III, respectively, indicating increased resistance to S. agalactiae infection in comparison with the control group. These findings contribute significantly to understanding the effectiveness of monovalent and bivalent vaccines against S. agalactiae in tilapia fry, informing the development of strategies for improved disease management and economic sustainability in tilapia aquaculture. |
| Year | 2024 |
| 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.;Zulfiqar, Farhad |
| Scholarship Donor(s) | AIT Scholarships |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2024 |