Hematological methods in fish – Not only for beginners

Abstract

Hematological analyses are commonly used to evaluate fish health and welfare in aquaculture, veterinary practice and scientific research. Hematological parameters were proved to be highly sensitive to various environmental factors including nutrition, water quality, stress or pathogens. Peripheral blood tests involve measurement of various red and white blood cells indices and are often supplemented by biochemical analyses. The use of hematological techniques is arduous and requires experience but high amount of information and relatively low cost are considerable advantages. Manual hematological methods that are most often used in fish hematology do not require highly specialized laboratory equipment, however automatic analysers adapted for use with fish blood are also in use. The results of hematological analysis may be affected by various preanalytical and analytical factors. The aim of this work was to review the procedures used in fish hematology by various authors. We develop recommendations that can provide practical guidance for fish biologists to help to obtain reliable and reproducible results.