Changes in selected haematological parameters at early stages of the rainbow trout, Oncorhynchus mykiss, subjected to metal toxicants: arsenic, cadmium and mercury

Abstract

Haematological responses (cellular alterations) induced 6 months post-treatment by three toxic metals, arsenic, cadmium and mercury, are reported. Treatment was at early stages of rainbow trout, Oncorhynchus mykiss, development. Different blood parameters (haematocrit level, red cells/mm3, white cells/mm3 red/white cell ratio and the white blood cell differential count) were examined in association with a histological examination. Significant differences were observed in the total number of leucocytes and the number of lymphocytes between the lesion-bearing fish of the arsenic and cadmium group and the healthy fish. Subsequently, the blood films showed atypical lymphocytes.