DAO 67:81-86 (2005)  -  doi:10.3354/dao067081

Subclinical Listonella anguillarum infection does not impair recovery of swimming performance in rainbow trout Oncorhynchus mykiss

Keith B. Tierney1,*, Shannon K. Balfry2, Anthony P. Farrell2

1Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
2Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada

ABSTRACT: This study examines whether injections of the commonly used bacterial-challenge pathogen Listonella anguillarum (formerly Vibrio anguillarum) negatively impact the ability of rainbow trout Oncorhynchus mykiss Walbaum to perform repeat swimming trials. Fish were given intraperitoneal injections of either a sub-lethal (105 colony forming units; CFUs) or a lethal (107 CFUs) dose of L. anguillarum, held for 48 h, and then given 2 successive ramp critical swimming speed (Ucrit) tests separated by 45 min. Compared with saline-injected control fish, the low-dose injection did not significantly impair swimming performance and recovery. Similarly, Ucrit and re-performance for fish surviving the high-dose injection were comparable to control (2 of 6 fish died after injection and before testing). In contrast, a positive control test of seawater challenge did impair recovery of swimming performance. In view of these results and common use of L. anguillarum as a challenge pathogen for toxicological studies, it seems unlikely that the consequences of pathogenesis impact the important cardiorespiratory changes associated with exercise.

KEY WORDS: Listonella anguillarum · Vibriosis · Seawater · Swimming performance · Recovery · Critical swimming speed · Ucrit

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