Effects of dietary Cirsium arvense essential oil on growth performance, digestive enzymes, and antioxidant parameters in rainbow trout, Oncorhynchus mykiss

The present study assessed the effects of dietary supplementation with Cirsium arvense essential oil (CAEO) on growth and antioxidant responses in rainbow trout, Oncorhynchus mykiss. Four diets were prepared containing 0 (CTR), 2 (CAEO2), 4 (CAEO4), and 6 (CAEO6) mL/kg CAEO and offered to fish (31.31±0.15 g) in triplicate for 60 days. Dietary CAEO significantly increased growth, feed efficiency, intestinal chymotrypsin, trypsin, serum superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Dietary CAEO significantly decreased serum malondialdehyde. The highest growth rate, gut chymotrypsin, and serum GPx were observed in CAEO6, whereas the highest feed efficiency, intestinal trypsin, serum SOD, and CAT, and lowest serum MDA were observed in CAEO4 and CAEO6. In conclusion, CAEO can be used as a feed additive for the aquaculture of rainbow trout, as it improves the production and antioxidant of the fish at a concentration of 6 mL/kg. © 2024 Iranian Society of Ichthyology.