Systemic and mucosal antibody response of Asian seabass, Lates calcarifer to monovalent and bivalent vaccines prepared from Streptococcus iniae and Streptococcus agalactiae | |
| Author | Nguyen Giang Thu Lan |
| Call Number | AIT Thesis no.AQ-19-06 |
| Subject(s) | Sea basses Giant perch Streptococcus agalactiae--Prevention Fishes--Vaccination |
| 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 | Asian seabass, Lates calcarifer farming encounters many unique disease challenges (mostly bacterial and viral) in a variety of aquaculture systems. Of these, the infection by Streptococcus represents a significant threat to seabass aquaculture production worldwide. Vaccination has been proven successful in the prevention of many dreaded infectious agents affecting humans and cultured animals, including fish. In this study, the specific antibody of the monovalent and bivalent inactivated vaccines was evaluated in Asian seabass after two months following intraperitoneal injection as a preventive strategy against Streptococcosis disease caused by Streptococcus agalactiae and Streptococcus. iniae. The primary inactivated vaccines (oil-based) were administered to the fish in a trial with four treatments (150 fish in each treatment): i) PBS + adjuvant (T1), ii) Streptococcus agalactiae + adjuvant (T2), iii) Streptococcus iniae + adjuvant (T3), and iv) Streptococcus agalactiae + Streptococcus iniae + adjuvant (T4) followed by booster doses administered after three weeks using inactivated vaccines without adjuvant (water-based). An enzyme-linked immunosorbent assay (ELISA) was applied to determine the systemic and mucosal antibody (IgM) responses of Asian seabass to S. agalactiae and S. iniae in different vaccine treatments. The efficacy of monovalent and bivalent vaccines was tested by a laboratory aquarium challenge after the antibody titer remained elevated for at least 9 weeks. The results revealed that the immune response in the fish vaccinated with the monovalent vaccine was significantly higher than that of the bivalent vaccine in terms of specific antibody titer in both systemic and mucosal systems. Systemic IgM increased significantly after 7 or 14 days post-vaccination with S. agalactiae and S. iniae, respectively, while the bivalent vaccine required a booster to see a significant difference from control groups. Interestingly, mucosal IgM was also significantly increased after the booster. At day 63 post-vaccination, both systemic and mucosal antibody titers remained higher than control groups. The monovalent and bivalent inactivated vaccines were found to be highly efficacious in Asian seabass after challenge test with the RPS of 75% to 85%. To our knowledge, this is the first achieved research in the monovalent and bivalent inactivated vaccine in Asian seabass against S. agalactiae and S. iniae. |
| Year | 2019 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| 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) | Salin, K.R. |
| Examination Committee(s) | Bhujel, Ram C.;Loc Thai Nguyen |
| Scholarship Donor(s) | AITCV Silver Anniversary Scholarships |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2019 |