title: Exposure to sublethal levels of PCB-126 impacts fuel metabolism and swimming performance in rainbow trout.
abstract: Polychlorinated biphenyls (PCBs) are recognized physiological stressors to fish which over time may impair individual performance and perhaps fitness by inducing changes that could have population-level consequences. PCB-126 (3,3',4,4',5-pentachlorobiphenyl) accumulates in lipids and can subsequently be released into the bloodstream during periods of high activity that involve the mobilization of stored fuels to meet with increasing energy demands. The goal of this study was to determine if a sublethal exposure to PCB-126 altered the content of tissue energy supplies (carbohydrates, proteins, amino acids, triglycerides) and impaired swimming performance as well as oxygen consumption in rainbow trout (Oncorhynchus mykiss). Trout were injected intraperitoneally with a single Low (100μgkg(-1)) or High (400μgkg(-1)) dose of PCB-126 then swimming performance and metabolic rates from 1 to 9days post-injection were compared to Control (non-dosed) fish. Liver ethoxyresorufin-O-deethylase (EROD) activity was assessed as an indication of PCB-126 intoxication while plasma and white muscle tissue metabolites were analyzed as an index of physiological disturbance. Swimming performance, assessed using two successive modified critical swimming speed (Ucrit) tests, was highest for fish in the High PCB-126 treatment; however, their initial condition factor (K) was also higher, largely due to their greater body mass. Trout in the High and Low PCB-126 treatments exhibited impaired recovery following intense exercise as they swam comparatively poorly when provided a second challenge. PCB-exposed fish exhibited reduced spleen somatic indices as well as muscle glucose and glycogen contents; whereas plasma cortisol and glucose levels were elevated, indicating higher metabolic costs during recovery and muscle restoration. Overall, this research provides insights into the sublethal effects of a toxic organic compound on swimming performance in trout.
authors.affiliation: Department of Biology, and Centre for Advanced Research in Environmental Genomics, University of Ottawa, 130 Marie-Curie, Ottawa, Ontario K1N 6N5, Canada; Fish Ecology and Conservation Physiology Laboratory, Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada. Electronic address: karyne.bellehumeur@canada.ca.
authors.forename: Karyne
authors.initials: K
authors.lastname: Bellehumeur
authors.affiliation: Fish Ecology and Conservation Physiology Laboratory, Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada.
authors.forename: Dominique
authors.initials: D
authors.lastname: Lapointe
authors.affiliation: Fish Ecology and Conservation Physiology Laboratory, Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Cooke
authors.affiliation: Department of Biology, and Centre for Advanced Research in Environmental Genomics, University of Ottawa, 130 Marie-Curie, Ottawa, Ontario K1N 6N5, Canada.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Moon
mesh_terms: D052436:Adipose Tissue, White / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004734:Energy Metabolism / Q000187:drug effects*; D005260:Female; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D017686:Oncorhynchus mykiss / Q000097:blood / Q000378:metabolism* / Q000502:physiology; D010101:Oxygen Consumption / Q000187:drug effects; D011078:Polychlorinated Biphenyls / Q000633:toxicity*; D013550:Swimming; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls; D019363:Cytochrome P-450 CYP1A1; C023035:3,4,5,3',4'-pentachlorobiphenyl
keywords: Critical swimming speed; Fitness; Metabolic rate; Oncorhynchus mykiss; Performance; Polychlorinated biphenyls; Recovery ratio