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).