title: Excess post-hypoxic oxygen consumption is independent from lactate accumulation in two cyprinid fishes.
abstract: Carassius carassius responds to hypoxic conditions by conversion of lactate into ethanol, which is excreted over the gills. However, a closely related species, Cyprinus carpio, does not possess the ability to produce ethanol and would be expected to accumulate lactate during hypoxic exposure. While the increase in oxygen consumption in fish required following strenuous exercise or low environmental oxygen availability has been frequently considered, the primary contributing mechanism remains unknown. This study utilized the close relationship but strongly divergent physiology between C. carpio and C. carassius to examine the possible correlation between excess post-hypoxic oxygen consumption (EPHOC) and lactate accumulation. No difference in the EPHOC:O2 deficit ratio was observed between the two species after 2.5h anoxia, with ratios of 2.0±0.6 (C. carpio) and 1.3±0.3 (C. carassius). As predicted, lactate accumulation dynamics did significantly differ between the species in both plasma and white muscle following anoxic exposure. Significant lactate accumulation was seen in both plasma and muscle in C. carpio, but there was no accumulation of lactate in white muscle tissue of C. carassius. These findings indicate that lactate accumulated as a consequence of 2.5h anoxic exposure is not a major determinant of the resulting EPHOC.
authors: University of Manitoba, Department of Biological Sciences, 369 Duff Roblin, 190 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada. janet.genz@ad.umanitoba.ca
authors: J
authors: J
authors: Genz
authors: M B
authors: MB
authors: Jyde
authors: J C
authors: JC
authors: Svendsen
authors: J F
authors: JF
authors: Steffensen
authors: H
authors: H
authors: Ramløv
mesh_terms: D000818:Animals; D002347:Carps / Q000378:metabolism / Q000502:physiology; D000431:Ethanol / Q000378:metabolism; D005880:Gills / Q000378:metabolism; D000860:Hypoxia / Q000378:metabolism / Q000503:physiopathology; D019344:Lactic Acid / Q000378:metabolism*; D009132:Muscles / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption
chemical_list: D019344:Lactic Acid; D000431:Ethanol; D010100:Oxygen