DAO 78:29-36 (2007)  -  DOI: https://doi.org/10.3354/dao01855

ABSTRACT: In this study, experiments were conducted to examine the effect of an acute necrotic bacterial gill infection on the metabolic rate (M_O2) of Atlantic salmon Salmo salar. Fed and unfed Atlantic salmon smolts were exposed to a high concentration (5 × 10¹² CFU ml^–1) of the bacteria Tenacibaculum maritimum, their routine and maximum metabolic rates (M_O2rout and M_O2max, respectively) were measured, and relative metabolic scope determined. A significant decrease in metabolic scope was found for both fed and unfed infected groups. Fed infected fish had a mean ± standard error of the mean (SEM) decrease of 2.21 ± 0.97 µM O₂ g^–1 h^–1, whilst unfed fish a mean ± SEM decrease of 3.16 ± 1.29 µM O₂ g^–1 h^–1. The decrease in metabolic scope was a result of significantly increased M_O2rout of both fed and unfed infected salmon. Fed infected fish had a mean ± SEM increase in M_O2rout of 1.86 ± 0.66 µM O₂ g^–1 h^–1, whilst unfed infected fish had a mean ± SEM increase of 2.16 ± 0.72 µM O₂ g^–1 h^–1. Interestingly, all groups maintained M_O2max regardless of infection status. Increases in M_O2rout corresponded to a significant increase in blood plasma osmolality. A decrease in metabolic scope has implications for how individuals allocate energy; fish with smaller metabolic scope will have less energy to allocate to functions such as growth, reproduction and immune response, which may adversely affect the efficiency of fish growth.

KEY WORDS: Tenacibaculum maritimum · Metabolic rate · Atlantic salmon · Feed ration ·Oxygen consumption · Bacteria · Exercise