ORAL VACCINATION

Method

Oral vaccination is achieved by mixing feed with vaccine (Press and Lillehaug, 1995). The fish then engulf the feed and associated vaccine.

These smolts are consuming fish feed that has been mixed with vaccine.

Pros of Oral Vaccination

• Welfare considerate relative to injection vaccination since no physical penetration by a needle is required thus eliminating any chance of local reactions, spinal deformities, intra-abdominal distortion or lesions, and granulomata 

Cons of Oral Vaccination

• Fish co-operation is required; the fish need to be feeding otherwise they will not ingest enough vaccine to elicit a strong humoral response
• Expensive method since large amounts of vaccine is required
• Weak strength & short duration of immunity provided relative to injection vaccination

Economic Concerns

• Relatively weak strength & short duration of immunity provided by vaccine meaning this method is not commonly used; the costs outweigh the short term immunity
• Excess amount of vaccine is required since salmon uptake is low and time consuming relative to injection vaccination, adding to production costs.