VPP 322: Aquatic Animal Diseases, Health Care and Management (1+1)

VACCINATION METHODS

Vaccination methods in fishes

• Injection into abdominal cavity (Intraperitoneal) / musculature (Intramuscular)
• Dipping
• Bathing
• Use of vaccine feed
• Spraying

Injection

• Injection method is the most widely followed method of vaccination although it cannot be used to vaccinate smaller fishes. It is the most efficient method of delivery of vaccination without wastage but involves handling stress to fish. When the injection method is used, fish is starved for at least two days before injection. Fish is sedated and injected, using a dosing syringe and 0.1-0.2 ml of undiluted vaccine. Fishes of size 15-40 g and above can be vaccinated by injection. Vaccines can be administered by injection in the abdominal cavity or musculature.

Injection method of vaccinating fish

Dipping

• In this method fishes are exposed to vaccines for few seconds to minutes after which they are transferred to the original rearing medium. Usually the propotion of the vaccine in the medium is 1:10 - 2:8 (depending on type and concentration) in 1 - 2 L of rearing medium which is sufficient for 100 kg of fish. The vaccine enters the fish mostly through the gills, but also through the skin and the gut. The use of the vaccine depends on the size of the fish. The method is less labour intensive than injection but not as effective.

Bathing

• In this method, vaccine is added directly to the tank and the fish is kept in the solution for an hour, before the water flow is reestablished. This way of vaccinating is the easiest but unfortunately also the least effective. Bathing and dipping are mostly used for small fish.

Vaccine feed

• Sometimes vaccines or antigens can be given in feed, absorbed through the gut of the fish which then forms an immunity. This method does not cause stress in fishes. The vaccine feed have to be fed continuously for 10 days.

Spraying

• Although vaccines can also be sprayed on fishes, it does not give good protection.