Effects of two commonly used anticoagulants on haematology and erythrocyte morphology of rainbow trout (Oncorhynchus mykiss)

Abstract

The present literature gives ambiguous information regarding the use of anticoagulants for fish blood collection. Many workers recommend the use of heparin as the preferred anticoagulant for routine haematology, however the salts of EDTA are also considered appropriate by some workers. The present study was, therefore, carried out with an aim to evaluate the effects of two commonly used anticoagulants i.e., lithium-heparin and di-sodium EDTA with a concentration of 20 I.U/ml and 1.0 mg/ml on the haematological parameters and erythrocyte morphology of coldwater fish Oncorhynchus mykiss. Haematological analysis including blood cell counts and haematocrit was done within one hour of the sampling. Samples collected with Na2EDTA showed increased haematocrit values. Haemoglobin concentration and red blood cell counts were lower in Na2EDTA collected samples as compared to heparinized samples, while WBC counts did not differ significantly (P>0.05). Mean corpuscular volume (MCV) was increased, while a significant decrease (P0.05) was observed in Li-heparin treated samples. The present study suggests the use of Li-heparin as a preferred anticoagulant for routine haematological analysis of fish blood.