HAEMATOXICITY, CONDITION AND ORGAN INDICES OF Heterobranchus bidorsalis TREATED WITH CYMBUSH UNDER LABORTAORY CONDITIONS
Keywords:
gonadosomatic index, pyrethroids, agrochemical, biomarkersAbstract
Heterobranchus bidorsalis (mean length 31.50 ± 2.32 cm SD; mean weight 241.25 ± 30.39 g SD) were exposed to
cypermethrin (5.00, 7.50, 10.00, 12.50 and 15.00 ppb) and a control (0.00 ppb) for 23 days. Fulton’s condition was
assessed at the beginning and end of the experiment. Organ (liver, kidney, heart and spleen) indices and
haematological variables: packed cell volume (PCV) haemoglobin, Hb; leucocrit, erythrocyte sedimentation rate
(ESR) white blood cells (WBC) thrombocytes, red blood cells (RBC) and their indices-Mean corpuscular
haemoglobin, MCH; Mean corpuscular hemoglobin concentration (MCHC) and mean corpuscular volume (MCV)
were determined. The haematological responses to the cymbush exposure were very variable relative to the
exposure concentrations. However, there was a decline in the PCV, WBC and lymphocytes (P < 0.05) values in
exposed fish compared to their control values. Highest decline in the blood variables, except in the value of
lymphocytes occurred at 150 ppb. Hb, leucocrit, eosinophil and neutrophil values in exposed fish were very
variable. Thrombocytosis was the most blood responsive variable (25 units at 150 ppb, above the control). ESR
value was generally raised in the exposed fish compared with the control (1.75 ± 0.48 mm/hr). RBC indices (MCHC,
MCH and MCV) in exposed fish did not vary (P ≥ 0.05) from the control. Fish condition generally declined from the
initial values but final condition was raised above the control in almost all the concentrations (P > 0.05). The
changes in the organ weights in exposed fish were variable except in the kidney. Results from this study indicate that
exposure to sub lethal levels of cymbush impacted mainly on the blood variables with minimal changes in the
condition and organ indices of the exposed fish. Hence, indiscriminate application of the insecticide should be
checked to reduce contamination of the aquatic environment to the barest minimum.
