Potential effects of Ocimum sanctum against cadmium-induced toxicity in freshwater fish, Cyprinus carpio

Abstract

This study explored the potential benefits of Ocimum sanctum (Tulsi) powder on Cyprinus carpio against waterborne exposure to cadmium (Cd). Fish (n = 180; average weight: 20.51 ± 0.23 g/fish) were randomly assigned to six groups, with three replicates per group, using 18 experimental tanks in total. Two control groups were established: a negative control group without Cd exposure or O. sanctum powder supplementation, and a positive control group exposed to Cd (3 μg/L CdCl₂) without O. sanctum powder supplementation. Remaining four groups received O. sanctum supplementation at varying levels (10–40 g/kg) alongside Cd exposure (3 μg/L CdCl₂). The 60-day trial showed that waterborne Cd exposure not only increased Cd deposition in various organs but also adversely affected fish carcass, growth performance, and hematology in C. carpio. However, Cd toxicity was significantly counteracted by dietary O. sanctum supplementation. Notably, supplementation of 30 g/kg improved carcass quality, enhanced growth performance, restored blood parameters, and reduced Cd accumulation in tissues. In conclusion, these findings suggest that dietary inclusion of O. sanctum at 30 g/kg significantly mitigates heavy metal toxicity and improves health and performance of C. carpio.