Ameliorative Impacts of Neem Leaf Powder on Cadmium Toxicity in Nile Tilapia: Growth Performance, Haemato-Biochemical, Oxidative and Pathological Insights

Abstract

Our research sought to clarify the impact of Neem Leaf Powder (NP) as a feed supplement in reducing the harmful effects of CdCl2 toxicity in Nile tilapia. Acclimated 360 fish were allocated randomly into 4 treatments with 3 repetitions in each group, including control group, CdCl2 intoxicated group (2 mg/L in water), and 2 groups fed on NP at 2 and 4 g/kg feed with exposure to 2 mg/L of CdCl2 for 60 days. Digestive enzymes, total protein, albumin, liver function indices (AST, ALT, and LDH), total cholesterol, and triglycerides, besides liver oxidant/antioxidant biomarkers (superoxide dismutase, catalase, glutathione peroxidase, glutathione S transferase) were measured using a spectrophotometer. Intestinal PCNA expression was detected using immunohistochemistry. Our data exhibited that tilapia exposed to water CdCl2 toxicity showed a significant decline in growth performance, feed utilization, fish survival, and intestinal digestive enzymes (protease, lipase, and amylase). Furthermore, CdCl2-intoxicated fish showed a substantial downregulation in hematological parameters, total protein, globulin, and some antioxidant indicators, including catalase, glutathione s-transferase, total and reduced glutathione, besides superoxide dismutase. Additionally, CdCl2 toxicity substantially upregulated albumin, glucose, liver enzymes, total cholesterol, triglycerides, glutathione peroxidase, and lipid peroxidation (LPO). The CdCl2 residues in the liver, gills, and muscles were significantly increased, particularly in hepatic tissues in the CdCl2-intoxicated group. Treatments with NP at both 2 and 4 g/kg diet impeded these deleterious effects by upregulating the growth parameters, hematological parameters, intestinal, hepatic, and antioxidant enzymes activities, with downregulation of LPO and lipid profile parameters with improvement in intestinal histoarchitecture.