Effect of adding Camelia siensies ‎extract on blood biochemical ‎parameters and liver enzymes in ‎Carassius auratus in exposure to ‎heavy metal Cadmium and ‎Mercury

Recently, plant protection products have become commonly used in aquaculture as immune stimulants to strengthen the fish safety system. Some plants are a rich source of tannins, polysaccharides, alkaloids, flavonoids, saponins, and polyphenols, which have been shown to play different roles, including having antimicrobial effects and strengthening the immune system of fish. In the present study, 150 goldfish (mean weight 135 g) were divided into three groups: control group (T1), metal + extract of green tea (T2) and metal (T3) with three replicates. The optimum dose of extract in fish diet was determined (0.65 mg/kg), sub-lethal concentrations of cadmium (0.5 mg/l) and mercury (0.5 mg/l). In order to study the biochemical parameters of blood, sampling was carried out on days 3, 7, and 14, after exposure to the concentration of heavy metals of cadmium and mercury. The results showed that total protein, cholesterol, glucose and the levels of lactate dehydrogenase (LDH), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) enzymes were significantly different in treatment of herbal extracts (T2) than other treatments. On the other hand, the values ​​of the mentioned indices in the treatment of metal containing the extract of the plant were significantly higher than other treatments (P<0.05). According to the results, it can be stated that increased the immunity system in fish that fed with plant extract and the biochemical parameters were optimally. Regarding the fact that heavy metals in water resources affect the biochemical parameters of blood of fish, the results of this study suggest that the use of herbal extract increases the fish's physiological capacity against the negative effects of environmental pollutants. Therefore, the use of Camelia siensies extract in fish is recommended to increase the physiological capacity and reduce liver damage in the exposure of wastewater and industrial contaminants.