SALMONIDS
W
3
WAYS TO IMPROVE SALMONID DISEASE RESISTANCE
by Benedict Standen & Rui Gonçalves, Biomin ith an increasing pressure to provide affordable protein to an evergrowing population, aquaculture practices are expanding and intensifying. High stocking densities can lead to animals becoming stressed and immunocompromised, while also favoring the proliferation of pathogens.
a
Unfortunately, disease outbreaks are inevitable and this represents a major constraint for the sustainable development of the industry. Nowhere is this more obvious than in high value species, such as salmonids, where disease outbreaks can lead to significant economic losses. Salmon culture is often considered the holy grail of aquaculture. Consequently, as an industry it has worked hard to reduce its dependency on antibiotics, relying primarily on vaccination for disease control. Although this approach has been effective, it also has its limitations. This is especially true in cold water fish because antibody production is temperature dependent: thus it can
b
Figure 1: Atlantic salmon with external appearance of a large ‘furuncle’ under the skin (a). Insert shows open furuncle and (b) opened peritoneal cavity of an Atlantic salmon with furunculosis showing extensive hemorrhaging in the peritoneal fat and wall (yellow arrows) and within muscle (red arrow). SOURCE: www.agriculture.gov.au
42 | May | June 2016 - International Aquafeed