The role of oregano herb and its derivatives as immunomodulators in fish

Abstract

AbstractThe motivation behind this article is to give point‐by‐point data about the beneficial applications of oregano feed supplement in fish diets as immunomodulators, antioxidant, antiviral, antifungal and antiparasitic. Use of this plant as feed additive plays an important role in the fish diet when compared to other synthetic feed additives. Oregano is rich in phytochemical compounds including carvacrol and thymol in addition to other phenolic compounds with antioxidant and immune‐enhancing activities. Origanum vulgare extract improved the immunological responses and enhanced non‐specific immunity. Also, non‐specific immunity and the lysosomal activity were significantly increased in rainbow trout fed diet enriched with 3.0 mL essential oil of Origanum onites L kg−1 diet for 60 days. Furthermore, non‐specific immune stimulant, antioxidant and nitric oxide activities were improved due to O. vulgare oil supplementation. In some recent studies, Origanum heracleoticum L essential oil as a growth enhancer increased the antioxidant status. In rainbow trout, the hepatic levels of antioxidant enzymes and the total antioxidant capacity increased by feeding diet enriched with 6 and 10 g kg−1 diet of O. vulgare extract. Therefore, the addition of oregano and/or derivatives as a dietary supplement in fish diet may promote growth and enhance the immunity and health of fish and this will be useful for nutritionists, physiologists and veterinarians.