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RESPIRATORY-CARDIOVASCULAR PHYSIOLOGY AND CHLOROETHANE GILL FLUX IN THE CHANNEL CATFISH ICTALRUS PUNCTATUS
Citation:
McKim, J., J. Nichols, G. Lien, AND S. Bertelsen. RESPIRATORY-CARDIOVASCULAR PHYSIOLOGY AND CHLOROETHANE GILL FLUX IN THE CHANNEL CATFISH ICTALRUS PUNCTATUS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-94/247 (NTIS PB94177714), 1994.
Description:
A fish respirometer-metabolism chamber was used to obtain in ivo respiratory-cardiovascular and chloroethane gill flux data on transected channel catfish (Ictalrus punctatus). ethods used for spinal transection, attachment of an oral membrane (respiratory mask), placement and attachment of blood cannulas and urine catheters are described. espiratory physiology, cardiac output and chemical extraction efficiencies for 1,1,2,2-tetrachloroethane (TCE), pentachloroethane (PCE), and hexachloroethane (HCE) were determined on 419-990 g catfish. he overall mean values (+/- .D.) for ventilation volume (Qv), effective respiratory volume (Qw), oxygen consumption (VO2), and percentage utilization of oxygen (U) were 17.3 +/- 4.7 1 h-1 kg-1, 9.8 +/- 1.71 h-1 kg-1, 71.6 +/- 12.5 mg h-1 kg-1, and 49 +/- 10%, respectively, while cardiac output calculated via the Fick Method was 2.4 +/- 0.61 h-1 kg-1. dditional measurements were made on ventilation rate (Vr), total plasma protein, hematocrit (Hct), and urine volume; while both arterial and venous blood were analyzed for pH, oxygen partial pressure (PO2), carbon dioxide partial pressure (PCO2), total oxygen (TO2), total carbon dioxide (TCO,) and total ammonia (TAMM). hysiological measurements taken at 24 h were not significantly different from those taken at 48 h and indicated no deterioration of the in vivo preparation. ll of these values agreed well with literature values on untransected channel catfish, except for Hct which was lower for cannulated animals used in this study. verall, these data provide strong support for the use of transected channel catfish for in vivo collection of physiological and chemical gill flux data. The mean initial chemical extraction efficiencies for TCE, PCE and HCE were 41, 61 and 73%, respectively. hemical clearances (Clx) for these same three chemicals were 5.9, 9.3 and 10.81 h-1 kg-1, respectively. he approximate 1:1 relationship between effective respiratory volume (Qw) and chemical clearance (Clx) indicated that branchial uptake of PCE and HCE was water flow-limited. hemical gill flux observed for channel catfish and chloroethanes was similar to that observed for rainbow trout in previous studies and provided further support for the flow-limited model of chemical flux across fish gills.