Submitted to: Global Aquaculture Advocate
Publication Type: Popular Publication
Publication Acceptance Date: February 11, 2003
Publication Date: February 20, 2003
Citation: Bilodeau, A.L., Wolters, W.R. 2003. Genetic detection of edwardsiella ictaluri: application in a channel catfish selective breeding program. Global Aquaculture Advocate 6:23-24. Technical Abstract: Sensitive detection of ESC (Enteric Septicemia of Catfish) is important to the successful development of a selective breeding program for ESC resistance in channel catfish. Therefore, a genetic assay using quantitative PCR (polymerase chain reaction) was developed for early detection of E. ictaluri DNA in channel catfish blood. This assay was applied to track the early stages of infection and to detect differences among fish populations/families that may have different levels of innate disease resistance. Initial uptake of the bacteria did not affect survival; however, susceptible fish had higher levels of bacteria 24 hours after exposure compared to resistant fish. Pathogen clearance was equivalent for both susceptible and resistant fish. This suggests that survival after ESC infection is not determined by clearance rates from blood, but that the immune system may suppress ESC infection in resistant fish. The genetic detection assay will improve selective breeding programs by providing an assessment of early stages of infection and an understanding of the mechanisms responsible for disease resistance.