ELISA-based segregation of adult spring chinook salmon for control of bacterial kidney disease. Annul report FY 1990

摘要

Bacterial kidney disease (BKD), caused by Renibacterium salmoninarum (RS), is 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 from the second year of a four year study to investigate segregation of broodstock as a tool for controlling BKD are presented. To segregate the progeny of adult fish infected with RS we have used enzyme-linked immunosorbent assays (ELISAs) optimized in the first year of this project. Gametes from fish 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. Screening of eggs from infected adults has not revealed any detectable antigen present in the egg tissue. Development of a rapid, field ELISA has been accomplished this year. The field ELISA utilizes monoclonal antibodies currently employed in the monoclonal antibody-based ELISA. The sensitivity of the field ELISA approaches that of the monoclonal ELISA, and has been tested on 150 adult chinook salmon. A high correlation exists between samples assayed by the monoclonal ELISA, field ELISA, and direct FAT. An alternative system for detecting RS soluble antigen, the Western blot, has also been improved. Using a chemiluminescent substrate, the sensitivity of detection has been increase 50--100 fold. 16 refs., 15 figs., 2 tabs.