A FIELD INVESTIGATION INTO THE EFFECT OF SEWAGE EFFLUENT AND GENERAL WATER-QUALITY ON SELECTED IMMUNOLOGICAL INDICATORS IN CARP (CYPRINUS-CARPIO L)

Carp were held in cages at several sites on a river catchment in South East England. Following exposure to river water, various indices of i mmune function were measured. These included in vitro lymphocyte proli feration assays, pronephric and splenic somatic indices and serum lyso zyme activity. A significant reduction in both the proliferative respo nses of T and B lymphocytes and in serum lysozyme activity was recorde d in groups of exposed carp in comparison with a control (high water q uality) site. The observed lysozyme differences were not reflected in total serum protein levels. Glucose assays were performed to assess ch ronic stress levels in the fish. This established whether immunologica l differences were a secondary response due to stress or a direct cons equence of water quality. Based on data presented here, it is suggeste d that the water quality in the River Lea exerts a detrimental effect on fish immunity. However, any additional detrimental effect of treate d sewage effluent on carp immunity was not apparent. (C) 1997 Academic Press Limited.