Effect of water temperature on experimental edwardsiella ictaluri infections in immersion-exposed channel catfish

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Abstract

The effect of water temperature on the progress of enteric septicemia of catfish was examined in channel catfish after immersion exposure to Edwardsiella ictaluri. Mortalities due to the bacterium were evaluated among experimentally infected fish held at 15, 20, 25, 30, and 35°C. One of the two replicate groups held at each temperature was shifted to 25°C water 60 d after exposure, and all groups were held for an additional 30 d. The greatest mortality occurred among E. ictaluri-exposed groups at 25°C (97.8%), but significant mortality also occurred among infected fish at 20°C (46.6%) and 30°C (25.0%). There was a lower mortality at 35°C (4.0%), and there was no mortality among fish at 15°C or among control fish at any temperature. There were no mortalities during the last 30 d of the experiment in any group shifted to 25°C or in the groups that were not transferred. The highest antibody titers among fish exposed to the bacterium were detected in fish held at 20°C; antibody titers were lower but detectable for fish held at 15, 30, or 35°C Antibody titers decreased in all groups after transfer to 25°C. Microscopic lesions in fish after 3 months were not remarkable, except for a chronic glomerulonephritis in fish exposed to the bacterium and held at 35°C. Results suggest that clinical expression of the disease is pronounced and mortality is increased at 2Q-30°C. The high antibody titers in infected fish, although not significantly different among the temperature groups, suggest that they are good indicators of prior exposure to the bacterium.

Original languageEnglish (US)
Pages (from-to)148-151
Number of pages4
JournalJournal of Aquatic Animal Health
Volume4
Issue number2
DOIs
StatePublished - Jan 1 1992

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ASJC Scopus subject areas

  • Aquatic Science

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