Panax ginseng essential oil as a dietary additive: growth and digestive enzyme benefits for rainbow trout

This study aimed to evaluate the effects of dietary ginseng, Panax ginseng, essential oil (GE) on the growth performance and digestive enzyme activities in rainbow trout, Oncorhynchus mykiss. Fish were fed diets containing 0 ml/kg (control; CTL), 0.5 ml/kg (GE0.5), 1.0 ml/kg (GE1.0), 1.5 ml/kg (GE1.5), 2.0 ml/kg (GE2.0), 2.5 ml/kg (GE2.5), 3.0 ml/kg (GE3.0), and 3.5 ml/kg (GE3.5) GE for 8 weeks. Results indicated that the highest growth performance and feed efficiency were achieved with the GE2.0 and GE2.5 treatments. The GE2.5 and GE3.0 treatments exhibited the highest activities of gut trypsin, chymotrypsin, and lipase. But there were no significant differences in the gut amylase activity among the treatments. In conclusion, dietary GE at 2.5 ml/kg is recommended for trout feed supplementation to reach the highest production.