Abstract

SUBCHRONIC TOXICITY OF DELTAMETHRIN AND TETRAMETHRIN IN NILE TILAPIA FISH

Rehab A. Mohammed*, Adel F. Tohamy, Mahmoud A. Mahmoud, Mohamed A. Elhady and Maher M. Soliman

ABSTRACT

Due to the massive use of pyrethroids in control of harmful organisms in agriculture, they may pollute the natural environment and so may reach the water. In this study we aimed to investigate the toxic effects of Delta larvae® (Deltamethrin 5% +Tetramethrin 2.5%) on Nile tilapia fish and the role of Lector 50® (Protector) against this toxicity. Nile tilapia were exposed to sublethal concentrations of Delta larvae® for 60 days. Haematological, biochemical, histopathological consequences and immunological changes were assayed at the end of experiment. The protective role of Lector 50® was also evaluated. The median lethal concentration of Delta larvae® in the Nile tilapia fish for 96 h was found to be 7 μg/l. We selected 1/20th of 96 h LC50 value of Delta larvae® (0.35 μg/l) for the subchronic toxicity study. Exposure to Delta larvae® not only significantly decreased neutrophils percentages, total leucocytic and haemoglobin percentage but also increased lymphocytes percentage. Serious effects in the form of significantly decreased serum acetylcholineestrase (AChE) activity, increased urea and creatinine levels were also observed. Moreover, the histopathological results indicated that the haemobiotic organs and most tissues were severely affected by Delta larvae. Our results suggest that the alterations in assayed parameters of fish may be useful in environmental biomonitoring and used as good biomarkers for pyrethroid ecosystem pollution to assess the health of fish in freshwater habitat contaminated with Delta larvae®.

Keywords: Deltamethrin, Tetramethrin, Nile tilapia fish, Subchronic toxicity, Lectin