Immunochemical Comparison Between sera from the Primary and Secondary Circulations in a Salmonid Fish, Sakhalin Taimen (Hucho perryi)

Abstract

Fish has a unique, non-respiratory vascular system called secondary circulation, which forms capillary networks to the internal and external body surfaces. We compared protein composition in serum from the secondary circulation with that from the primary (blood) circulation. Chromatographic and electrophoretic patterns of sera from the two circulations were essentially same. Immunochemical analysis using specific antibodies against albumin-like protein (α1-protein), immunoglobulin M (IgM), transferrin, vitellogenin and choriogenin (precursor to eggshell protein) revealed that these major blood serum proteins in the primary circulation are present in the secondary circulation. Total protein concentrations in the secondary circulation were lower than those in the primary circulation. α1-Protein levels in the secondary circulation relative to the primary circulation were similar to those of total protein. IgM, however, had significantly lower relative levels in the secondary circulation than total protein. Despite some differences in the protein composition between the primary and secondary circulations, the presence of major blood serum proteins in the secondary circulation suggests that the secondary circulation plays a role in transporting them from the primary circulation to the body surfaces.