The effects of pyrene exposure on gill O2 respiration and osmoregulation in channel catfish

Abstract

The present study examined whether pyrene exposure alters gill function in channel catfish, a species with impermeable skin and gills that function as the primary gas exchange and osmoregulatory organ. Following a 7‐day, in‐water treatment of catfish to control or pyrene water, animal O2 consumption was measured. Blood samples were then collected and analyzed for the hematocrit, ion and protein concentrations, plasma osmolality, and hemoglobin concentration and red cell water content. Pyrene exposure produced significant decreases in water O2 uptake and plasma Na+ concentration, and significant increases in hematocrit and plasma osmolality in pyrene‐exposed fish. However, there were no significant changes to the red cell water content, and the hemoglobin, plasma protein, and K+ concentrations. These data suggest that in‐water pyrene exposure significantly damaged the gill tissue, thereby leading to reduced O2 uptake and altered osmoregulation. Catfish were kindly provided by the Jake Wolf Fish Hatchery and the Fountain Bluff Fish Farm in Illinois. Funding was provided by the Sherry Endowment and Bjorklund Research Funds, and the Bradley University Biology Department and LAS Dean's Office.