Over the last three decades Infectious Salmon Anaemia (ISA) has periodically caused high mortality in Atlantic salmon ( Salmo salar ) aquaculture. The severity of the outbreaks in terms of mortality levels and virus detection (both virulent and low /non-virulent) has varied both within and between sites and has primarily been handled by stamping out, removing affected cages, or intensified surveillance.
PHARMAQ developed an ISA challenge model in 2002, and later demonstrated proof of concept for an ISA vaccine based on a European subtype of the virus. Vaccine efficacy was further demonstrated in evaluated challenge models (both IP and cohabitation), which contributed to the documentation of multi- (ALPHA JECT® 5-1 and ALPHA JECT ® micro 7 ISA ) vaccine for salmonid markets .
The last decades there have also been an intensification of smolt production in all markets mainly caused by larger hatcheries, often with RAS technology. The combination of technologies result in off-season smolt production based on different smoltification protocols where different light regime s and smoltification feed, are among the most used. There are concerns related to suboptimal smoltification creating stress and further suppressed immunity (both specific and unspecific) and vaccine response . The current study evaluates different smoltification protocols followed by vaccination with ALPHA JECT ® micro 7 ILA and by ISAV challenge (both IP and cohabitation). The vaccine efficacy against experimental challenge and applicability combined with experiences from commercial use of our ISA vaccines will be presented , together with discussions related to best practice smoltification protocols combined with timing of vaccination.
The use of experimental animals was approved by the Norwegian Food and Safety Authority and internal ZOETIS Animal Ethics Committee.