Some age related changes of adult rainbow trout, Salmo gairdneri Rich., peripheral erythrocytes separated by velocity sedimentation at unit gravity

Velocity sedimentation at unit gravity separated peripheral erythrocytes of adult rainbow trout according to age and size. The cells located at the top of the gradient contained numerous polyribosomes, few mitochondria and an essentially electronlucent nucleus. The cells at the bottom of the gradient no longer contained these cytoplasmic organelles and had an essentially electron-dense nucleus. The middle of the gradient contained cells with either very few polyribosomes or cells devoid of this organelle.
The length, width and mean corpuscular volume (MCV) of the average cell increased and the width to length ratio decreased progressively from the top of the gradient to the bottom.
No Statistical significance could be determined in the changes of the mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) although they appeared to follow theoretical projections.
The use of haematocrit, red cell count, haemoglobin concentration, MCV, MCH and MCHC in assessing erythropoietic activity and the size and haemoglobin content of the maturing cell is discussed.