Meeting Abstract

P3.147  Thursday, Jan. 6  Respiratory function response to acute bacterial exposure in the American lobster, Homarus americanus BRINGS, Victoria E.; JORGENSEN, Darwin D.*; Roanoke College; Roanoke College jorgensen@roanoke.edu

Bacterial infection in some crustacean arthropods invokes an immune response involving the cardiovascular and respiratory systems. Hemocytes are mobilized in response to infection, engulf bacterial cells, and are carried by the hemolymph to the gill circulation where, it has been suggested, they embolize in small diameter gill hemolymph channels. It is hypothesized that the aggregation of hemocytes in the gill circulation will impair respiratory function. We monitored ventilation and oxygen uptake in American lobsters (Homarus americanus) before, during, and after injection of the bacterium, Vibrio campbellii. Hemolymph pressure drop was concurrently measured across the gill circulation to estimate its hemolymph flow resistance. Lobsters injected with bacteria showed a 30% decrease in oxygen uptake and a concurrent 50% increase in hemolymph pressure drop across the gill circulation within about one hour. Oxygen uptake and pressure drop were unaffected by injection of sterile saline in control experiments. Heart rate remained unchanged in both sets of experiments. Our data show that respiratory capability is compromised after acute bacterial exposure in lobsters and may result from the aggregation of hemocytes in the gill circulation, which may impede hemolymph flow through gill circulatory channels.