Dietary Nigella sativa oil confers protection against diazinon toxicity in nile tilapia (Oreochromis niloticus): a detoxification-based approach

This study evaluated how dietary black seed oil (Nigella sativa L.) against the diazinon waterborne toxicity on Nile tilapia (Oreochromis niloticus), focusing on growth performance, hematological and biochemical parameters as well as oxidative stress markers and histological changes. A 40-day feeding trial was carried out using four experimental groups: Group 1 (control group), Group 2 (N. sativa-supplemented group), Group 3 (diazinon-exposed group), and Group 4 (diazinon-exposed with N. sativa supplementation group). The LC₅₀ value of diazinon for Nile tilapia was determined to be 4.642 mg/L, and fish were exposed to a sublethal concentration of LC₅₀/20 during the trial. Results demonstrated that diazinon exposure significantly impaired growth, hematological parameters, and liver function while increasing oxidative stress and tissue damage. Conversely, dietary supplementation with N. sativa oil significantly mitigated these adverse effects by enhancing specific growth rate, restoring RBC, Hb, and Hct values, improving liver enzyme profiles, and increasing antioxidant enzyme activity (SOD, CAT, GPx). Histological examinations confirmed that N. sativa oil reduced diazinon-induced damage in gill and liver tissues. The results show that N. sativa oil can be used as a functional feed ingredient to enhance fish resistance to chemical stressors that are commonly found in intensive aquaculture.