title: Metabolic capacities of common carp (Cyprinus carpio) following combined exposures to copper and environmental hypoxia.
abstract: In aquatic ecosystems, a decline in water O2 level is the main factor that can release heavy metal ions from top sediment layer. Therefore, hypoxia in turn, and in association with heavy metals might provide undesirable environment and impairs physiological functions of aquatic animals. To address this, metabolic capacities, including standard metabolic rate (SMR), maximum metabolic rate (MMR), aerobic scope (AS) and factorial aerobic scope (FAS) of common carp were determined following exposures to different levels of water-borne Cu(2+) as well as hypoxia. Treatments for Cu(2+) were included: 100% (acute), 50% (sub-lethal) and 10% (chronic) of LC50-96h for immediately, 24h and 7 days exposures respectively. Hypoxia treatments were assigned as acute for immediately, sub-lethal for 24h and chronic for 7 days. Combined effects of treatments were also considered as acute Cu(2+)+hypoxia, sub-lethal Cu(2+)+hypoxia and chronic Cu(2+)+hypoxia. While SMR of carp was reduced by chronic hypoxia, significant (P<0.05) increase was observed during acute hypoxia, as compared with control. The MMR and AS were significantly reduced (P<0.05) following all hypoxia treatments. The acute and chronic Cu(2+) treatments showed significant (P<0.05) increases in SMR and MMR values. All acute and sub-lethal combined treatments showed significant (P<0.05) reductions in SMR, MMR and AS values, whilst chronic combined treatments showed generally increasing trends for MMR and AS. PCrit was relatively reduced following all treatments except for acute and sub-lethal Cu(2+)-treated fish that showed higher value (P<0.05) and no change respectively. Although all Cu(2+) treatments increased the number of mucus cell, hypoxia treatments did not show any remarkable differences when compared with control group. In general, the results of present study reveal that hypoxia acts as limiting stressor whilst Cu(2+) do act as loading stressors in the case of common carp metabolism. The interactive exposures mostly showing a synergist effect in all metabolic capacities with an exception for chronic treatments.
authors.affiliation: Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran. Electronic address: p.malekpouri@gmail.com.
authors.forename: Pedram
authors.initials: P
authors.lastname: Malekpouri
authors.affiliation: Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
authors.forename: Rahim
authors.initials: R
authors.lastname: Peyghan
authors.affiliation: Fisheries Division, Department of Natural Resources, Isfahan University of Technology, Isfahan 8415683111, Iran.
authors.forename: Nasrollah
authors.initials: N
authors.lastname: Mahboobi-Soofiani
authors.affiliation: Department of Pathobiology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
authors.forename: Babak
authors.initials: B
authors.lastname: Mohammadian
mesh_terms: D000818:Animals; D002347:Carps / Q000378:metabolism / Q000502:physiology*; D003300:Copper / Q000378:metabolism / Q000633:toxicity*; D005618:Fresh Water / Q000737:chemistry*; D005880:Gills / Q000187:drug effects; D018384:Oxidative Stress / Q000502:physiology; D010100:Oxygen / Q000502:physiology*; D013312:Stress, Physiological / Q000502:physiology; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D003300:Copper; D010100:Oxygen
keywords: Aerobic scope; Copper; Critical oxygen tension; Gill histopathology; Oxygen consumption