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Aquatic Toxicology
Elsevier
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Abstract: |
Little is known about the effects of oxyfluorfen, a diphenyl ether herbicide, exposure on the African catfish
(Clarias gariepinus) health. Consequently, the existing investigation was designed to highlight the impacts of
oxyfluorfen exposure on C. gariepinus hematological indices, liver and kidney functions, reproductive hormones,
and oxidative status. Furthermore, a consequent 10-day depuration period was adopted to evaluate the recovery
of the disturbed indicators to normal values. In the first experiment, the 96-h lethal concentration 50 (LC50) of
oxyfluorfen for C. gariepinus was determined using probit analysis. Next, in a second experiment, 180 healthy
fish (average initial body weight: 164.23 ± 0.24) were randomly assigned to 4 experimental groups exposed to
0, 1/10, 1/8, or 1/5 96-h LC50 of oxyfluorfen. The hematological profile, hepatic enzymes, kidney damage
byproducts, reproductive hormones, oxidative stress, and lipid peroxidation indicators together with acetylcholinesterase (AChE) content were assessed. A histopathological examination of the hepatic, renal, brain, and
testicular tissues was accomplished. Moreover, the expression of the oxidative stress-related gene was carried
out. The results showed that 96-h LC50 of oxyfluorfen for C. gariepinus was 11.698 mg/L. Exposure to sublethal
levels of oxyfluorfen induced macrocytic hypochromic anemia, leukopenia, lymphopenia, monocytopenia, and
eosinopenia. Also, a concentration-dependent increase in alanine transaminase, alkaline phosphatase, aspartate
transaminase, urea, creatinine, catalase, and malondialdehyde was detected following oxyfluorfen exposure
together with upregulation of catalase gene. But, significant concentration-dependent reductions in AChE,
glutathione transferase, reduced to oxidized glutathione ratio, estradiol, and testosterone activities were recorded. These biochemical alterations were accompanied by pathological perturbations in hepatic, renal, brain,
and testicular tissues. Following 10 days of recovery, only the hematological impairments were abolished.
Conclusively, the herbicides oxyfluorfen could induce multiple negative impacts on C. gariepinus with oxidative
stress as a probable underlying mechanism. Additionally, a recovery period of 10 days was not enough to restore
these impairments.
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