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Polymerase Chain Reaction Amplification of Genetic Loci from Diseased Channel Catfish Found Dead in Ponds
Author(s) -
Waldbieser Geoffrey C.
Publication year - 1996
Publication title -
journal of aquatic animal health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 52
eISSN - 1548-8667
pISSN - 0899-7659
DOI - 10.1577/1548-8667(1996)008<0155:pcraog>2.3.co;2
Subject(s) - catfish , ictalurus , biology , polymerase chain reaction , ictaluridae , microbiology and biotechnology , genetics , gene , fish <actinopterygii> , fishery
As part of a selective breeding program for farm‐raised channel catfish Ictalurus punctatus , we screened diseased fish to identify genetic markers linked to disease resistance or susceptibility. Because many diseased fish in ponds are not detected until after death, we investigated the utility of DNA isolated from diseased channel catfish found dead in ponds. Channel catfish (4–25 g) diagnosed with enteric septicemia of catfish or saprolegniasis were sampled 24–48 h postmortem from infected ponds. Control fish were killed by anesthetic overdose and sampled immediately. Total DNA isolated from liver, muscle (with skin), and caudal fin was quantified and analyzed for degradation. Yield of purified DNA, measured as micrograms of DNA per milligram of tissue, was significantly (P < 0.05) lower in diseased fish than in controls. Two sets of DNA primers were used to amplify a portion of the channel catfish growth hormone gene and the mitochondrial D‐loop region with the polymerase chain reaction. Degradation of DNA in liver and the caudal fin of some diseased fish inhibited successful amplification. Amplification of fragments up to 1,000 base pairs long from genomic DNA of postmortem channel catfish will be useful for identifying molecular genetic markers linked to disease susceptibility.