Stress Protein Expression in Coho Salmon with Bacterial Kidney Disease

Abstract

The expression of stress protein-70 (SP-70), also known as heat shock protein-70 (HSP-70), was measured by enzyme-linked immunosorbent assay in kidney and liver from coho salmon Oncorhynchus kisutch with bacterial kidney disease (BKD) experimentally induced by injection with Renibacterium salmoninarum. Fish with BKD had more SP-70 in both kidney and liver than did the control fish. The SP-70 measured was derived from the host tissue, not from the pathogen. In fish without clinical disease, SP-70 was not significantly elevated. Elevated stress protein (SP) levels in fish with BKD raise the possibility that BKD or other infectious diseases may interfere with the use of SP induction as a marker of environmental stress in fish and lead to statistical artifacts when the prevalence of disease is not considered.