Evaluation of in vivo non-specific immunity and oxidative stress in Labeo rohita (Hamilton, 1822) infected with Aeromonas hydrophila as biomarker for early diagnosis

Abstract

Labeo rohita Hamilton, 1822, was challenged with asymptomatic dose of Aeromonas hydrophila to study innate immune responses. Significant (p > 0.01) alterations were observed in haematological, biochemical parameters viz. white and red blood cell counts, haemoglobin content, haematocrit, leucocrit, MCV, MCH, MCHC, dWBC % (neutrophil, eosinophil, lymphocytes, monocytes), total protein, albumin, globulin, albumin : globulin ratio, glucose, calcium, bilirubin, alkaline and acid phosphatase activity in serum in treated and control fishes after 7 days exposure. ROS production increased significantly in exposed fishes along with increased SOD and Catalase activities. Aggregation of melanomacrophage centers and modifications were observed in the histopathology of liver. Annexin V/ PI study indicated higher percentage of apoptotic cells in liver of infected fishes. Re-isolation and detection of A. hydrophila was done by Duplex PCR. Potent exposure biomarkers have been successfully screened and can be used for the development of rapid diagnostic technique of A. hydrophila infection.