BactiVac and IVVN workshop on vaccines for tilapia

16 Oct 2019

Dr Ngô Huỳnh Phương Thảo, Biotechnology Center of Ho Chi Minh city, Vietnam, Dr Rowena Hoare, University of Stirling, UK, and Dr Kim Thompson, Moredun Research Institute, UK, hosted a workshop on vaccines for tilapia at Biotechnology Center of Ho Chi Minh City on 23rd-25th September 2019.

This three day workshop was held as part of the BactiVac catalyst project 'Optimisation of novel mucosal vaccines to prevent bacterial diseases of Tilapia (Oreochromis niloticus)' led by Dr Rowena Hoare. Other partners who attended included Prof Sandra Adams and Mr William Leigh from the University of Stirling, UK.

Tilapia is one the most important species farmed in low and middle income countries (LMIC). Vietnam (a LMIC) and Thailand are important contributors to tilapia production in South East Asia, with tilapia aquaculture currently expanding in both countries. The majority of diseases in tilapia are bacterial, with treatment by antibiotics common. Although tilapia is a well-established cultured species globally, there are few effective commercial vaccines available or used in this species. The majority of fish vaccines are multivalent oil-adjuvanted and given by injection. While they provide good protection against bacterial and viral pathogens, they have some drawbacks such as side effects and can only be delivered by injection. Mucosal vaccination of fish- by immersion and oral (in-feed) routes- has many benefits over injection: cost of application, mass vaccination of juveniles, less handling stress leads to less side effects and infections. At present, a limited number of mucosal vaccines are available for fish, primarily due to them being less effective than injection vaccines with shorter duration of immunity. The benefits of application of vaccine to fish by immersion or oral routes are numerous; ease of application being the foremost especially in less developed countries where expensive vaccination machines are not feasible for farmers. Many fish farmers in LMIC countries would benefit from immersion and oral vaccines that can protect their stocks for the duration of production. Development and optimisation of mucosal vaccines is essential to provide protection of aquaculture species worldwide and contribute to reducing the use of antibiotics and thereby antibiotic resistance. Through the collaboration of scientists from the UK, Thailand and Vietnam, we are modifying an existing monovalent vaccine for a bacterial disease of tilapia, Francisella noatunensis subsp. orientalis (Fno), as a proof of concept to demonstrate the benefits of mucosal vaccination in our BactiVac Catalyst project. The technology has the potential to be expanded to encompass other bacterial pathogens of fish in future polyvalent vaccines.

Workshop participants

Workshop delegates

A total of 62 participants attended the workshop, which was open to fish producers, vaccine companies and academics specialising in vaccine development and fish health from the South East Asia region through additional funding awarded to Dr Ngô Huỳnh Phương Thảo from IVVN’s workshop fund and Pharmaq (Zoetis) funding. As well as projects partners, 32 scientists were invited from Vietnam, and 30 scientists from Bangladesh, Malaysia, Indonesia and Thailand (Figure 1). The purpose of the workshop was to discuss how best to disseminate the results, transfer technologies, decide on future funding strategies for follow-on funding and the best way to promote this work to obtain maximum impact from the project results. There were also presentations on the present updates on the disease status of tilapia aquaculture in the region and discussion on how scientists could help develop effective mucosal vaccines for aquatic animals.

The workshop was opened by the director of the Biotechnology Center of Ho Chi Minh City, Dr Dương Hoa Xô.

Other speakers at the workshop included William Leigh (University of Stirling, UK), Ho Thu Thuy (Envina, Vietnam), Dr Angela Mariana Lusiastutiis (Research Institute for Freshwater Aquaculture and Fisheries Extension, Indonesia), Dr Ina Salwany (Universiti Putra Malaysia, Malaysia), Prof Md Ali Reza Faruk (Bangladesh Agricultural University, Bangladesh), Dr Tanvir Rahman, Dr Sébastien Deville (Seppic, France), Nguyen Giang Thu Lan (Asian Institute of Technology, Thailand), Dr Patai Charoonnart (Mahidol University, Thailand), Sarocha Jitrakorn (BIOTEC, Thailand), Terje Tingbø (Pharmaq, Norway) and Dr Truong Dinh Hoai (Vietnam National University of Agriculture, Vietnam).

Discussions at the workshop

Tilapia

Some important points were discussed at the workshop with respect to administering mucosal vaccines to tilapia:

  • Modern techniques are needed for the production of effective and cheap vaccines for tilapia as it is a low value fish species.
  • The presence of unknown pathogens in aquaculture ponds is threatening not only the farmers but also the scientists in the disease management and treatment.
  • The collaborations between vaccine companies and scientists are needed for the widespread application and commercialisation of aquatic vaccines in countries in Southeast Asia.
  • More conversations are needed between farmers, scientists and vaccine companies to promote the usage of vaccines in aquaculture.
  • Scientists from different countries, who are interested in developing vaccines against the common pathogens should collaborate in a project to increase the impact of the project results.
  • Concurrent infections are now the norm in tilapia culture. These complicate vaccine design, making vaccines more expensive and the co-infections can affect the fish’s ability to response to the vaccine. Only healthy fish should be vaccinated for an optimal immune response to be induced by the vaccine.
  • The major pathogens currently causing big problems in tilapia culture in Southeast Asia include Streptococcus agalactiae, Steptococcus iniae, Aeromonas spp. (A. hydrophila and A. veronii), Edwardsiella spp. (E. tarda and E. ictaluri), iridovirus and Francisella noatunesis subsp. orientalis (Fno).

Visit to a tilapia farm

Tilapia farm

On the third day of the workshop, the delegates had the opportunity to visit a tilapia farm in Cai Lay, Tien Giang to observe red tilapia fry and fingerling production procedure from earthen ponds.