ELISA-Based Segregation of Adult Spring Chinook Salmon for Control of Bacterial Kidney Disease: Annual Report 1991.

摘要

Bacterial kidney disease (BKD), caused by Renibacterium salmoninarum (RS), a serious disease of salmonid fish worldwide. The disease has a major impact on spring chinook salmon populations in the Columbia River system. There is strong evidence that RS can be transmitted from parent to progeny, and segregation of progeny based on levels of antigen detected in adult fish may obviate this mode of transmission. Results are presented from the third year of a four year study to investigate segregation of broodstock as a tool for controlling BKD. Segregation of adult fish infected with RS has been achieved using enzyme-linked immunosorbent assays (ELlSAs) optimized in the first and second year of this project. Gametes from both 1990 and 1991 broodstock, either injected with erythromycin or receiving no antibiotic injection were successfully segregated into groups having either high or low levels of the RS soluble antigen. Offspring have been monitored every three months from the 1990 broodstock and are being monitored from the 1991 broodstock. Antigen levels in the offspring from the 1990 segregation experiment at Marion Forks Hatchery were low and clinical BKD was not observed in any of the juvenile fish. At Carson National Fish Hatchery, antigen levels were also low in fish which were sampled December 1990 through July 1991. Total mortality was low throughout these sampling periods. An increase in mortality was observed in November-December 1991, and preliminary evidence suggests that motality may have been due BKD. The epizootic appears to have equally effected both offspring from high and low RS antigen level parents. Antigen levels in moribund fish are being examined to confirm the prevalence of RS infection.