Protective effect of pomegranate peel (Punica granatum) ethanolic extract on common carp (Cyprinus carpio) exposed to cadmium

Cadmium (Cd) is a heavy metal that is considered a strong pollutant due to its long half-life in soil and high solubility in water. This metal is toxic and the main pollutant of aquatic ecosystems. In the present research, the effect of adding pomegranate peel extract in the diet of common carp (Cyprinus carpio) on inhibiting oxidative damages caused by experimental poisoning with cadmium has been evaluated. In this study, fish with an average weight of 70 g were randomly divided into five groups of twenty. The first group, without receiving any feed additive was considered as a control. The second group of fish was only exposed to cadmium chloride (5 mg/l). The third, fourth, and fifth groups, in addition to cadmium (5 mg/L), they also received 1, 2, and 4% concentrations of pomegranate peel extract, respectively. After the end of the test period, which was 140 days, the blood collection was taken from the samples. Then, the biochemical parameters in the blood serum of each sample were measured. The evaluation of the activity of enzyme indicators showed that cadmium consumption significantly decreased the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx) and total antioxidant capacity (TAC), while the level of malondialdehyde (MDA) increased significantly (p<0.05). Also, the results showed that the addition of increasing concentrations (1, 2 and 4%) of pomegranate peel extract significantly increased the activity of SOD, GPx, and TAC enzymes, while the MDA level decreased compared to the group treated with cadmium (p<0.05). Therefore, it seems that the use of pomegranate peel extract as a feed supplement can be useful to mitigate the effects of experimental poisoning caused by cadmium in common carp, although more studies are needed in this field.