Hematological changes associated with experimental infection of Aeromonas hydrophila in Oreochromis niloticus (Linné, 1758)

Abstract

Blood cell profile in tilapia Oreochromis niloticus associated with experimental infection of Aeromonas hydrophila was evaluated. For this purpose, a three-repetition experimental device was performed on fish of Oreochromis niloticus (35.1±11.8 g) infected with two concentrations of a suspension of Aeromonas hydrophila and their hematological parameters were evaluated after 48 hours. Red blood cells decreased significatively (p<0.05) indicating an anemic condition. The decrease also affected hematocrit, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration and hemoglobin. White blood cells, the main defense cells of the animal increased significatively (p<0.05) further indicating sensibility of the animal to stress and infection. Lymphocytes and eosinophils increased significatively (p<0.05). This increase is a physiological response to stress. Neutrophils and monocytes decreased, indicating a response to stress and sensibility of the animal to infection. Thus, Aeromonas hydrophila induces serious consequences on hematological parameters on fish of Oreochromis niloticus, which justifies its pathogenic power in this fish.