Intervet at World Aquaculture 2005

1 December 2005

To mark the launch of our first vaccine (against Streptococcus iniae infections) in farmed warm-water fish in Asia, a technical seminar on ‘Fish vaccination in the Asia-Pacific region” was held a few months ago at the World Aquaculture 2005 conference in Bali. Presentations covered issues from challenges in ensuring the sustainability of Asian aquaculture to the role of vaccination in aquatic animal disease management in the region. 

The seminar was organised by Intervet’s Aquatic Animal Health (AAH) R&D centre in Singapore and Intervet Indonesia. It was chaired by Dr. Zilong Tan, Manager, Veterinary Services, Intervet Norbio Singapore. There were over 70 participants from 12 countries, representing fish farmers, governmental and inter-governmental agencies, research institutes, universities and fish health practitioners. It also coincided with the introduction of the first fish vaccine, Norvax® Strep Si, in Indonesia. As this streptococcus pathogen affects many marine and freshwater fish species throughout the region, we expect that registration of the vaccine in other countries will be completed over the next few years. 

In his opening address at the seminar, Dr. M Fatuchri Sukadi, (former) Director General of the Directorate General of Aquaculture, Ministry of Marine Affairs and Fisheries (DGA-MMAF), said, “Finally we have a solution to combat diseases in the Asian seabass industry and this may be a starting moment for the application of fish vaccination in Indonesia.” [Since then, Intervet has actually helped set up the first commercial fish vaccination team in Indonesia]. 

Dr. Rohana Subasinghe of the Food and Agriculture Organisation (FAO) in his presentation on challenges for sustainability of aquaculture in Asia, said that, at the same time as Asia’s contribution to the production of farmed fish continues to rise, the methods of fish production are under scrutiny. The rapid development of aquaculture has, for some commodities, outstripped planning and regulatory activities. This has in turn evoked a bad reputation for aquaculture as a means of fish production.

In Asia, readily available antibiotics have provided a certain level of protection against bacterial diseases in fish. However, consumers are concerned with antibiotic residues and the health risk they present. “Today, our challenge is not only to look at efforts to maintain sustainability but also at the production of safe and quality aquatic products. Issues on ethical means of production will soon follow. Our farming systems should assure food safety and meet demands on traceability”, he said.

Dr. Subasinghe added that Asian producers need to increase production efficiencies. Improvements in husbandry must be linked with total disease management. In disease management, R&D on vaccines for diseases affecting Asian aquatic animal species has accelerated in the last few years.  “However, although aquaculture is expanding in terms of volumes, there is the need for more consistent yields. We need to learn from experiences in the salmon industry in Norway which, over a period of ten years, increased efficiency of production exponentially. This was achieved by vaccination replacing antibiotics and through concurrent developments in production, feeds and feeding”, said Rohana.

According to Dr. William Enright, Marketing Manager, Intervet AAH Division, Atlantic salmon farming has led the way for many developments in intensive fish farming, particularly in the field of vaccination. Since 1993, there has been a rapid rise in production yields and this has coincided with various vaccine introductions leading to a concurrent decline in the use of antibiotics (see figure above). 

Developments in feeds and feeding, selective breeding, husbandry practices and health management have led to increases in production efficiencies. The acceptable survival rate is more than 95% in comparison to the less than 50% acceptable for marine fish in Asia. With relatively low costs of production, salmon has shifted from being a luxury product to that of a commodity. Regarding vaccine development for salmonids, resources have focused on a single family of fish (as compared with dozens in Asian aquaculture). This has allowed for good disease information and knowledge of the immune system to be established, resulting in vaccines now being available for most of the bacterial and viral pathogens affecting salmonids. Indeed, the most widely used vaccine, Norvax® Compact 6, is a combination vaccine against five bacterial pathogens and one viral pathogen.
  
Dr. Sylvie Quiniou, Research Molecular Biologist and Immunologist at the Catfish Genetics Research Unit of the USDA presented an elaborate talk on fish immunology and vaccinology. She also emphasized that, for vaccination to be effective, it has to be carried out together with good management strategies. Vaccination must be part of the overall health management and production process.

In his presentation on the role of vaccination in managing diseases in Asian aquaculture, Dr. Luc Grisez, Research Manager at Intervet Norbio Singapore, said that many diseases are prevalent in warm-water fish in the region. To date, except for Japan, no commercial fish vaccines are available in Asia.  “Asia accounts for 90% of global aquaculture production and represents a potential market for fish vaccines. However, the many and varied fish species cultured and the lack of etiological and epidemiological data on most of them have resulted in the absence of fish vaccines for its aquaculture to date. Intervet is now launching its first Asian fish vaccine”.  

The ideal vaccine, according to Luc, has to be safe and efficacious when applied. It is also important to balance easy application methods with a long-lasting effect. For the farmer, it is important to determine an acceptable level of mortality and the cost-benefit ratio of using a particular vaccine to reduce mortalities. In the case of losses due to Streptococcus infections in Asian seabass, Luc added, “It is important to look at the stage when the pathogen affects the fish. Losses due to mortality of fingerlings at the initial stocking stage may not cost much as fingerlings are cheap and easily replaceable. But cumulative mortality over the culture period can reach 70%”.