Activities of pretilachlor and pyribenzoxim herbicide on the behaviour and blood profile of juvenile Oreochromis niloticus fish

This work determined the effects of pretilachlor herbicide on behavioural and haematological parameters of juvenile Oreochromis niloticus at different concentrations. One hundred and eighty (180) apparently healthy fish were obtained and randomly distributed into 18 plastic tanks (75×45×45 cm) filled with 30,000 mL of unchlorinated water of six treatments (0.0, 0.10, 0.125, 0.15, 0.175 and 0.2 mL), in triplicate, of ten fish per tank for 96 h. 3 mL of blood was collected from each treatment after 96 h with a syringe and emptied into Ethylene Diamine Tetracetic Acid bottles. The 96-hour LC50 of toxicity was 1.03 mL. The behavioural responses of O. niloticus to the treatments are loss of reflex, erratic swimming, and air gulping. The haematological parameters were significantly different (p>0.05). There was decrease in Pack cell volume (22.50 ± 0.50 to 19.00 ± 2.00), Red blood cell (2.65 ± 0.55 to 1.75±0.45), Haemoglobin (7.50 ± 0.17 to 6.33 ± 0.67), White blood cell (3.15 ± 0.95 to 1.05 ± 0.05) and Mean Cell Hemoglobin Concentration (33.18 ± 0.14 to 33.14 ± 0.20), while there was an increase in Mean Corpuscular Volume ( 89.14±20.39 to113.11 ± 17.66 ) and Mean Corpuscular Haemoglobin (29.71±6.80 to 37.70 ± 5.89). Hence, the discharge of Pretilachlor herbicide in the aquatic environment should be restricted to reduce potential risk to fish.