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

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 (U_crit) tests separated by 45 min. Compared with saline-injected control fish, the low-dose injection did not significantly impair swimming performance and recovery. Similarly, U_crit 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 · U_crit