The effect of dietary n-3/n-6 polyunsaturated fatty acid ratio on salmonid alphavirus subtype 1 (SAV-1) replication in tissues of experimentally infected rainbow trout (Oncorhynchus mykiss).
Salmon pancreas disease (SPD) is one of the most commercially significant viral diseases of farmed Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) in Europe. In this study, the potential for dietary mitigation of the disease using different polyunsaturated fatty acid (PUFA) profiles was assessed in rainbow trout. We experimentally infected fish with salmonid alphavirus subtype 1 (SAV-1), the causative agent of SPD. These fish were fed two diets with different n-3/n-6 PUFA ratio (high omega 3, 3.08, and high omega 6, 0.87). We assessed the influence of the diets on the fatty acid composition of the heart at 0 days post infection (d.p.i.) (after 4 weeks of feeding the experimental diets prior to SAV-1 infection), and sampled infected and control fish at 5, 15 and 30d.p.i. Viral E1 and E2 glycoprotein genes were quantified by two absolute real-time PCRs in all the organs sampled, and significantly lower levels of the virus were evident in the organs of fish fed with high omega 6. Characteristic pathological lesions were identified in infected fish as early as 5d.p.i., with no significant differences in the pathology lesion scores between the two dietary regimes. This study shows that decreasing the n-3/n-6 PUFA ratio in experimental diets of rainbow trout changes the fatty acid content of the fish, and is associated with reduced SAV-1 replication in rainbow trout.
Institute of Aquaculture, University of Stirling, FK9 4LA Scotland, UK. Electronic address: benjamin.lopez-jimena1@stir.ac.uk.
Benjamin
B
Lopez-Jimena
Institute of Aquaculture, University of Stirling, FK9 4LA Scotland, UK.
Philip
P
Lyons
Institute of Aquaculture, University of Stirling, FK9 4LA Scotland, UK.
Tharangani
T
Herath
Institute of Aquaculture, University of Stirling, FK9 4LA Scotland, UK.
Randolph H
RH
Richards
Institute of Aquaculture, University of Stirling, FK9 4LA Scotland, UK.
Michael
M
Leaver
Institute of Aquaculture, University of Stirling, FK9 4LA Scotland, UK.
J Gordon
JG
Bell
Institute of Aquaculture, University of Stirling, FK9 4LA Scotland, UK.
Alexandra
A
Adams
Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Near Edinburgh, Scotland, UK.
Kim D
KD
Thompson
D000524:Alphavirus / Q000502:physiology*; D018354:Alphavirus Infections / Q000378:metabolism / Q000662:veterinary*; D000818:Animals; D004042:Dietary Fats, Unsaturated / Q000378:metabolism / Q000494:pharmacology*; D015525:Fatty Acids, Omega-3 / Q000378:metabolism; D043371:Fatty Acids, Omega-6 / Q000378:metabolism; D005393:Fish Diseases / Q000378:metabolism / Q000821:virology*; D009206:Myocardium / Q000378:metabolism; D017686:Oncorhynchus mykiss; D010182:Pancreatic Diseases / Q000378:metabolism / Q000662:veterinary* / Q000821:virology; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D014779:Virus Replication / Q000187:drug effects / Q000502:physiology
D004042:Dietary Fats, Unsaturated; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6
Rainbow trout; Salmonid alphavirus; Viral tissue distribution; n-3/n-6 PUFA