HEMATOLOGICAL PARAMETERS AS INDICATORS OF TOXIC STRESS PRODUCED BY MYCOTOXIN FOOD CONTAMINATION IN THE EUROPEAN CATFISH (Silurus glanis L.)

Hematological indices are important parameters for the evaluation of fish physiological status. The aim of the present study was to obtain a basic knowledge of the hematological response of the European catfish under the action of toxic metabolites (aflatoxin B) secreted by the mold Aspergillus flavus, but also the assessment of the physiological changes. The sampling of catfish blood from the two variants (infected and uninfected fish) before and after the experimental trial allowed the determination of the hematological indices. The erythrocyte count (EC) was done in an improved Neubauer haemocytometer, using the Vulpian reagent as dilution, following the method of Svobodova. The microhaematocrit method of Blaxhall and Darsley was employed in the determination of blood haematocrit, assessed through the centrifugation of capillaries to 12 000 rpm. The haemoglobin content of blood samples was determined by the Sahli hemoglobinmeter method. The hematological indices: mean cell volume (MCV), mean cell hemoglobin (MCH) and mean cell hemoglobin concentration (MCHC) were calculated using the formula of Svobodova. In the infected fish with aflatoxin, a decrease of RBC (-16.24%), PVC (-6%), Hb (-18.2%), MCH (-2.12%) and MCHC (-13.3%) and an increase of MCV (+11.5%) was observed, compared to uninfected fish. The decrease of the number of erythrocytes, the amount of haemoglobin and haematocrit in the blood of infected fish led to the installation of a state of anemia.