Enhancement of oxidative defence and growth performance of Nile tilapia by omega-9-rich freshwater fish oil

Abstract

© 2018 by Maejo University. Freshwater fish oil (FFO) was extracted from adipose tissue of freshwater hybrid catfish and evaluated for its physical and chemical properties. The clear yellow oil showed properties similar to those of commercial fish oil. Interestingly, the omega-9 monounsaturated fatty acid content of the FFO is four times that found in marine fish oil. Fish feed was formulated with the FFO and fed to Nile tilapia in cages for four months. Growth performance including body weight, weight gain and average daily gain of the Nile tilapia treated with feed supplemented with 1% and 1.5% FFO dramatically increased (p < 0.05) and the feed conversion rate decreased significantly. Moreover, the malondialdehyde level also significantly decreased in the plasma, liver and kidney of the fish fed with 0.5%, 1% and 1.5% FFO. In addition, glutathione levels increased significantly in erythrocytes of Nile tilapia fed with 0.5% and 1.0% FFO. The findings indicate that FFO can improve both the growth performance and oxidative defence in Nile tilapia. The oil enhances oxidative defence by decreasing lipid peroxidation and increasing endogenous antioxidants. Therefore, FFO can be supplemented in fish feed, replacing marine fish oil, to improve growth and decrease the cost of aquaculture.