Protective Effects of Vitamin E and Selenium Nanoparticles Against Mercury Induced Growth, Blood and Histopathological Changes in Tilapia, Oreochromis niloticus

Achoimre

ABSTRACT Introduction Heavy metal pollution, especially from mercury (Hg), poses a significant risk to the aquatic organisms. The present study examined the effectiveness of dietary selenium nanoparticles (SeNP) or vitamin E in mitigating mercury‐induced physiological effects including growth and feed utilisation, blood biochemical indices, histopathological changes in gills and intestine in Nile tilapia, Oreochromis niloticus . Materials and Methods After 15 days of acclimation, 20 fingerlings of tilapia were released in each glass aquaria having four conditions such as control (free from test chemical/additives), mercury (Hg; 0.03 mg/L), Hg + Se (Hg; 0.03 mg/L, and selenium; 3 mg/kg feed) and Hg + Vit‐E (Hg; 0.03 mg/L, and vitamin E; 100 mg/kg feed) with three replicates for each treatment. The trial was lasted for 42 days. After the culture period, the fish were sampled and growth, feed conversion, blood profiles (i.e., glucose and haemoglobin), blood cytology (i.e., erythrocytic cellular and nuclear structures) and histopathology of gills and intestine were evaluated. Results The present study finds that chronic exposure to mercury significantly ( p < 0.05) reduced growth, altered blood biochemistry (i.e., increased glucose and haemoglobin), enhanced erythrocyte cellular and nuclear deformities and significantly higher pathologies in histology of gills and intestinal tissues. However, the current study recorded significant mitigation of growth inhibition, restoration of blood profiles and improvement of histological lesions following the incorporation of SeNP or vitamin E into the basal diet. Supplemented group experienced significantly better WG, SGR, FCR and survival, moreover blood glucose, haemoglobin and erythrocytic perturbations were normalised along with a lesser frequency of lesions in gills and intestine, suggesting significant restoration of physiological damage instigated by mercury exposure. Conclusion Therefore, these findings can be an effective tool in managing heavy metal‐induced toxicity resulting physiological damage in cultured fishes, including tilapia.