Effects of vitamin C on structural changes in the tissues of the giant African catfish, Heterobranchus longifilis exposed to Zinc Oxide nanoparticles
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Date
2021-09-07
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Abstract
Heterobranchus longifilis juveniles (n = 450, Mean length ± SD = 10.28 ±
1.34 cm) were exposed to varying concentrations (0 = control, 6.00, 8.00,
10.00, 12.00 mg/l) of zinc oxide nanoparticles (ZnO-NPs) for 60 days to
determine its effects on the histopathology of the gill and liver. To evaluate
recovery from ZnO-NPs exposure, fish were subjected to a 30-day
depuration. Ascorbic acid (AA) ameliorative potential against ZnO-NPs
toxicity was assessed by augmenting fish basal diet with different AA
(50.00, 250.00, 500.00, 1000.00 mg.kg-1) levels. After each experiment, fish
gills and liver were removed for histopathological analysis. Gills of exposed
fish revealed different alterations like epithelial hyperplasia, epithelial
lifting, lamellar fusion, oedema, aneurysms, and necrosis; while alterations
such as nuclear vacuolation, fatty degeneration, cytoplasmic degeneration,
focal fibrosis and necrosis were recorded in the liver. The mean degree
tissue change (DTC) in both organs of ZnO-NPs-exposed fish gradually
increased with increase in ZnO-NPs concentration and exposure period.
After 30-day depuration, some of the lesions in both organs attained
recovery, while others did not. AA administration to ZnO-exposed fish at
500 mg.kg-1 completely reversed the lesions in both organs compared to the
normal tissue architecture in the control. The results suggest that ZnO-NPs
could trigger structural alterations in both the branchial and hepatic tissues
of H. longifilis, and full recovery under depuration was slow. However, 500
mg.kg-1 AA dietary supplementation have the propensity to ameliorate the
ZnO-NPs-induced pathological lesions in H. longifilis.