Laboratory brook trout were used to evaluate, refine, or develop biochemical procedures for the analysis of fish blood. Analytical values were obtained for the following blood properties : total and differential leucocytes and erythrocytes; erythrocyte and plasma proteins (by electrophoresis) ; plasma refractive index; erythrocyte sedimentation rate; erythrocyte osmotic fragility; blood surface tension and density; haemoglobin; and packed cell volume. These blood factors are discussed with reference to fish health and disease and to changes caused by deleterious quantities of water pollutants.
I. INTRODUCTIONKnowledge of the composition of fish blood and of the function of blood components is fundamental to a comprehensive understanding of the normal and pathological biology and biochemistry of fish. Such information is particularly important when interpreting the changes induced by water pollutants or other abnormal environmental factors. To establish reliable diagnostic blood and tissue tests for identifying systemic and metabolic dysfunctions of fish, more fundamental information is needed on normal fish blood and tissue, fish metabolism, and the variability of metabolic components.This report presents a study and review of some analytical procedures applicable to the study of certain fish blood factors that may be relevant to bio-physiological responses of fish to toxic water pollution and adverse environmental conditions. Some of the procedures have not been thoroughly investigated in fish.The following blood factors were analyzed in adult brook trout (Salvelinusfontinalis) maintained in the laboratory: total and differential leucocytes (thrombocytes, lymphocytes, and neutrophils) and erythrocytes (mature and immature); erythrocyte proteins and plasma proteins (by electrophoresis); plasma refractive index; erythrocyte sedimentation rate; erythrocyte osmotic fragility; blood surface tension; blood density; haemoglobin ; and packed cell volume.