This study aimed to assess the levels of pyrethroids and organochlorine residues in the tissues of cultured Mugil
capito and in water samples obtained from three different sites (Al-Hamol, Al-Riad and Sidi Salem; referred to as
Area 1, Area 2, and Area 3, respectively) in the Delta region, Egypt. The study also assessed the biochemical
markers in exposed mullet and evaluated the impact of these residues on the expression of insulin-like growth
factor 1 (IGF-1) in muscle and cytochrome P4501A (CYP1A) in liver tissues using qRT-PCR and SDS-PAGE
methods. The results revealed that pesticide residue levels in the water were variable, but were lower than
detected levels in fish. Significant (P < 0.05) differences were found across the three study areas in terms of
serum ALT, but the serum AST level was not significantly (P > 0.05) elevated in all study regions. Serum
creatinine and urea levels were significantly (P < 0.05) elevated in area 3. Furthermore, glutathione and
malondialdehyde concentrations significantly increased (P < 0.05) in liver tissues in area 3. Using the qRT-PCR
technique, the results revealed that the expression level of IGF-1 was most significant in area 3, while the
expression level of CYP1A was most significant in area 1. The protein profile showed some differences in band
numbers and molecular weights of protein bands across different regions. Overall, the alteration in biochemical
parameters revealed pesticide interference with the metabolic processes of fish. Furthermore, the pesticide
pollution had an effect on the expression of IGF-1 and CYP1A genes and led to changes in the protein profile.
Therefore, these markers can be used to monitor fish distress following exposure to the pollutant.