Effects on haematological and serum biochemical parameters of Pangasianodon hypophthalmus to an experimental infection of Thaparocleidus sp. (Monogenea: dactylogyridae).

Monogenea (gill parasite) is a major problem in aquaculture that reduces the growth of cultured fish and adversely affects the economy. The present study was performed to evaluate the impact of various degrees of Thaparocleidus sp. (dactylogyrids, monogenean) infestation on haematological and serum biochemical parameters of Pangasianodon hypophthalmus. A standard cohabitation study, following complete randomized design in triplicate, was conducted to obtain low, moderate and high degrees of infestation in P. hypophthalmus along with the control (uninfested) group. Blood and serum were studied for haematological (total erythrocyte count (TEC), haemoglobin (Hb), packed cell volume (PCV), total leucocyte count (TLC) and indices viz. mean cell volume (MCV), mean cell haemoglobin (MCH), mean cell haemoglobin concentration (MCHC) and erythrocyte osmolarity brittleness (EOB)) and serum biochemical parameters (serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), lactate, total bilirubin and creatinine. Significant (p < 0.05) increase in TEC, Hb, TLC, EOB, SGOT, SGPT, LDH, lactate, bilirubin, and creatinine were noticed in moderate to high monogenean-infested group in comparison to the control group. However, significant (p < 0.05) reduction in MCH, and MCV and no difference (P > 0.05) in PCV were noticed in high degree parasitized group in comparison to the control group. The results of altered haematological and serum biochemical parameters in various degrees of monogenean-infested groups signify the density dependent physiological responses and changes in cells of the blood. The data of serum enzymes in the present study would be valuable for assessing the health status of the host and facilitate as a potential biomarker in relation to various degrees of monogenean infestation.