Publisher: Nofima AS
Number of pages: 23
International Standard Numbers:
Open Access: green
Commercially reared Atlantic salmon were fed a lean, protein rich test diet or a standard energy dense diet prior to, during and a period after a natural disease outbreak (07.2015) associated with PRV and SAV3 co-infection. The feed ingredients were the same in both diets. The test group had 11 % units lower frequency of dark spots and also significantly fewer fillets with serious large spots at slaughter. The occurrence of spots was higher in net pens with high mortality for salmon fed the standard diet, but the prevalence of dark spots was stable of the test group fed the lean diet. The proportion of salmon classified as “superior” by the slaughterhouse was 91 % for the test diet and 79 % for the standard diet. PRV was detected in skeletal muscle, kidney and heart, independent of the occurrence of dark spots. The amount of PRV virus in fillets decreased with time after the outbreak. The major feed effects on the response to SAV3 & PRV co-infection in form of decreased mortality, growth, proportion of “superior” salmon, and prevalence and severity of dark fillet spots at slaughter, shows that decreasing the fat level and increasing the protein level is advantageous with today’s blend of ingredients in feeds for Atlantic salmon.