Plasmid injection of rainbow trout. The rainbow trout strain used in the
studies presented here was a cross between the Klamath strain (Klamath Hatchery,
Chiloquin, Oreg.) and the Cape Cod strain (Roaring River Hatchery, Scio,
Oreg.). Eggs from both strains were obtained from their corresponding hatcheries
and then fertilized at the Oregon State University Salmon Disease Laboratory,
Corvallis. Fry were held in 100-liter tanks until the fish mean weight was
0.5 g at 2 months posthatch. Fish were then randomly assigned to one of five
groups of fish. Each group of 200 fish received one of the vaccines or phosphatebuffered
saline (PBS)