Author(s): Preeti Tirkey, Kalpana Baghel and Dr. Malabika Sikdar

Abstract: The widespread and indiscriminate use of pesticides manifolds the possibility of undesirable toxicity in aquatic organisms. Malathion (M) is a commonly used organophosphorus pesticide that adversely affects the physiology of aquatic organisms (mostly fishes), but is less studied. The present study examines the protective effects of thymoquinone (a bioactive compound of Nigella Sativa) on malathion-induced toxicity in haematological parameters and the gills of Labeo rohita (L. rohita). To achieve this, mature L. rohita were taken and randomly divided into four groups (n=7/group) where Group - 1 was kept as control (C), Group - 2 was exposed to Malathion (M), 2 μg/L for 30 days, Group - 3 was treated with Thymoquinone (TQ) alone i.e., 5 mg/kg body weight/day, and Group - 4 was exposed with M followed by TQ i.e., M+TQ supplementation for 30 days. After completion of the experiment, fishes were sacrificed; gills were dissected out from the body for further analysis. To find the toxic effect of M on gills, histopathological changes and alterations in various biochemical indices including lipid peroxidation (LPO), nitrite content (NO), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) activity were measured. Malathion-induced blood toxicity is indicated by low RBCs, WBCs and platelet count. M exposure group shows damage in gills with an augmented amount of mucus on the gill’s lamellae, pillar cells (PC) and hyperplasia. M exposure lowers the anti-oxidant enzyme activity as indicated by low SOD, CAT, GPx and GR activities in gills. On the other hand, TQ treatment clearly indicates the recovery of the ultrastructure of gills i.e., primary lamellae (PL), secondary lamellae (SL) and PC as evident by the scanning electron microscopy (SEM). In addition, the anti-oxidant activities of TQ reveal its protective effect on the gills of L. rohita. Therefore, the findings corroborate the fact that M causes damage to gills and increases oxidative stress. Whereas, TQ protects against the malathion-induced toxicity in the gills of L. rohita.

DOI: 10.22271/fish.2024.v12.i5a.2963

Pages: 24-34  |  163 Views  81 Downloads

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