Submitted to: Proceedings of International Congress on Biology of Fishes
Publication Type: Abstract Only
Publication Acceptance Date: 4/25/2003
Publication Date: 7/22/2003
Citation: DAVIS JR, K.B., GRIFFIN, B.R., GRAY, W.L. EFFECTS OF CONFINEMENT STRESS AND CORTISOL ON THE SUSCEPTIBILITY OF CHANNEL CATFISH TO INFECTION BY ICHTHYOPTHERIUS MULTIFILIIS AND CHANNEL CATFISH VIRUS.. PROCEEDINGS OF INTERNATIONAL CONGRESS ON BIOLOGY OF FISHES. 2003. p. 33 Interpretive Summary:
Technical Abstract: Many diseases of fish are referred to as opportunistic to indicate that the pathology caused by the infectious agent usually occurs after the protective mechanisms of the fish have been suppressed. Immunosupression and disease outbreakes often follow an episode of stress, which can be induced by a variety of conditions frequently encountered in aquaculture. One of the primary stress responses is the secretion of cortisol which can induce gluconeogenesis and suppression of the inflammatory response. The role of cortisol in increasing disease susceptibility is difficult to assess when fish are stressed by physical means due to the other physiological responses which also occur. The objective of the present study was to determine if confinement stress and the chronic administration of cortisol changed the susceptibility of channel catfish to infection by ich and to channel catfish virus (CCV). Channel catfish were either stressed by exposure to low water or fed cortisol mixed in the diet and then exposed to known trophont densities of ich or to known amount of plaque forming units of channel catfish virus. The data suggest that extended confinement in low water and orally administered cortisol increases the susceptibility of channel catfish to infection by ich but not to mortality due to CCV. The defense mechanisms which protect fish from parasite infections may differ from those which protect against virus infection and confinement stress and cortisol may differentially affect these defense systems.