Measurement of blood volume in the fish (Salmo gairdneri gairdneri)

Abstract

The volume of blood in the steelhead trout ( Salmo gairdneri gairdneri) was determined by the simultaneous use of radioactively labeled human serum albumin (HSA-I131), Evans blue dye (T-1824), and radioactively labeled red blood cells (RBC-Cr51). Blood volume derived from the plasma-hematocrit method utilizing Evans blue dye = 3.5 ± 0.9; for labeled albumin = 3.3 ± 0.9; through simultaneous use of both dye and labeled albumin = 2.9 ± 0.9. Blood volume obtained directly through the sum of the plasma and packed red cell volumes as measured with either Evans blue dye or labeled albumin and tagged red blood cells = 2.8 ± 1.0. Values are expressed as per cent of body weight and are in agreement with those that have been reported in the literature for bony fishes (Osteichthyes).