title: Effect of hypoxia on specific dynamic action and postprandial cardiovascular physiology in rainbow trout (Oncorhynchus mykiss).
abstract: Fish routinely encounter hypoxic environments, which may have detrimental effects on digestion and performance. The present study measured oxygen consumption (MO2), gastrointestinal blood flow (GBF), cardiac output (Vb) and heart rate (f(H)) in rainbow trout Oncorhynchus mykiss at 10°C-11.5°C while exposed to a 1.5-h step-wise hypoxia treatment (80%, 60% and 40% saturation=16.7, 12.6 and 8.4 kPa, respectively), which began 4 h after being fed 1% of their body mass. GBF and f(H) significantly decreased by 41 and 25%-29%, respectively, at the most severe hypoxia step (40% saturation), while MO2 and Vb were maintained throughout the entire hypoxia exposure. Thus, GBF and f(H) were more sensitive to hypoxia than MO2 or Vb in digesting rainbow trout. Subsequent to the hypoxic exposure, the fish were returned to normoxia and monitored for a total of 50h after feeding. While the magnitude of SDA was unaffected, peak postprandial MO2 was reduced by 17%, and the duration of specific dynamic action (SDA) was prolonged by 6h in hypoxia-treated fish when compared to control fish. In conclusion, digestive performance was compromised both during and after the hypoxic exposure, which could lead to negative effects on growth.
authors.affiliation: Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC,Canada, V6T 1Z4. Electronic address: eliason@zoology.ubc.ca.
authors.forename: Erika J
authors.initials: EJ
authors.lastname: Eliason
authors.affiliation: Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC,Canada, V6T 1Z4; Faculty of Land and Food Systems, University of British Columbia, 2357 Main Mall, Vancouver, BC, Canada, V6T 1Z4.
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Farrell
mesh_terms: D000818:Animals; D002302:Cardiac Output / Q000502:physiology; D002320:Cardiovascular Physiological Phenomena; D041981:Gastrointestinal Tract / Q000098:blood supply; D006339:Heart Rate / Q000502:physiology; D000860:Hypoxia / Q000503:physiopathology*; D017686:Oncorhynchus mykiss / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D019518:Postprandial Period / Q000502:physiology*
keywords: Digestion; Fish; Gut blood flow; Heart rate; Heat increment; Oxygen consumption; Specific dynamic action