Protective effects of summer savory (Satureja hortensis) oil on growth, biochemical, and immune system performance of common carp exposed to pretilachlor herbicide

There are many reports on the deleterious effects of herbicides on aquatic organisms which lead to tremendous biological, environmental and economical damage. In this regard, in the present study, the protective effect of summer savory (Satureja hortensis) essential oil (SEO) against pretilachlor, one of the most used herbicides was investigated in common carp (Cyprinus carpio). The fish assigned to six treatment groups (T1: control treatment; T2: 25% LC50 pretilachlor herbicide; T3: 50% LC50 pretilachlor herbicide; T4: 1% SEO; T5: 25% LC50 pretilachlor herbicide + 1% SEO; and T6: 25% LC50 pretilachlor herbicide + 1% SEO) for 21 days. The results showed that the SEO-containing treatments significantly increased the survival rate (SR) (P < 0.05). The highest final weight (FW), specific growth rate (SGR), and feed conversion ratio (FCR) were observed in the T4 treatment (P < 0.05). There was a significant increase in glucose (GLU) level in pretilachlor treatments and a significant decrease in SEO-containing treatments compared to the control (P < 0.05). The significantly highest total protein (TP) content was observed in T4 treatment containing SEO. Cholesterol (CHOL) and triglyceride (TRIG) levels decreased in SEO-containing treatments with the lowest level in T4 treatment (P < 0.05). Alternative complement pathway activity (ACH50), activity levels of superoxide dismutase (SOD), and glutathione peroxidase (GPX) showed an increasing trend in SEO-containing treatments with the highest level in T4 treatment (P < 0.05). The activity of liver enzymes showed a significantly lowest level in T4 treatment. To conclude, our findings revealed that the use of SEO in fish exposed to pretilachlor herbicide could improve growth, strengthen the immune system and exert a protective effect on common carp.