Hematological and physiological effects of viral erythrocytic necrosis (VEN) in Atlantic cod [Gadus morphua] and herring [Clupea harengus harengus]

The effects of viral erythrocytic necrosis (VEN) on clinical blood parameters and erythrocyte metabolism were investigated in Atlantic cod (Gadus morphua) and Atlantic herring (Clupea harengus h.). VEN-infected cod and herring exhibited lower hematocrits (HCT) and erythrocyte counts (E) in comparison to uninfected fish. In addition, VEN-infected cod, but not herring, had significantly lower hemoglobin concentrations (HB). No effects on plasma electrolyte or protein concentrations in either species were detected. Several metabolic changes were noted in VEN-infected erythrocytes. Infected cod erythrocytes had significantly lower lactate dehydrogenase (LDH) and glucose-6-phosphate dehydrogenase (G-6-PD) activities than erythrocytes from uninfected fish. No alterations in citrate synthetase (CS) activity were observed. No effects on LDH, G-6-PD, or CS activity were detected in VEN-infected herring. In VEN-infected cod erythrocytes the ATP levels were decreased approximately 50% compared to uninfected fish. In contrast, VEN infection in herring was associated with an elevation of ATP levels by approximately 33%.