Effects of different dietary oil sources on growth performance, antioxidant capacity and lipid deposition of juvenile golden pompano Trachinotus ovatus

Abstract

Vegetable oils (VO) that are used to substitute fish oil in aquafeeds may affect, not only the fatty acid composition, but also lipid metabolism and distribution. The present study was designed to investigate this issue in juvenile golden pompano Trachinotus ovatus fed eight diets formulated with typical VO with widely varying fatty acid compositions including coconut oil (CO), palm oil (PO), oil-tea camellia seed oil (OTO), olive oil (OO), canola oil (CNO), peanut oil (PNO), linseed oil (LO) and perilla oil (PFO), in comparison with fish fed fish oil (FO). After the 8-week feeding trial, fish fed the CO diet had the highest growth performance, and higher general antioxidant capacities in serum and liver than in fish fed the other VO. The crude lipid content in whole body and expression levels of fas were lower in fish fed the FO, PFO and LO diets, while lipid contents and expression levels of scd were higher in fish fed the OTO and PNO diets. Other than fish fed the PFO diet, the total lipid contents of liver in other fish fed the other VO diets were higher than that in fish fed the FO diet, with the highest contents in fish fed the OTO and OO diets. The expression levels of genes involved in fatty acid catabolism and transport, namely pparα, cpt1 and apoB100, were higher in fish fed diet PFO than in fish fed the other diets. Comparing the fatty acid compositions of tissues and diets showed that 18:1n-9, 18:3n-3 (ALA) and 22:6n-3 (DHA) were preferentially deposited in tissues of pompano, with DHA preferentially deposited in polar lipids rather than neutral lipids. However, excessive dietary ALA in PFO did not lead to increased deposition of ALA, but increased liver lipid content. The present study showed that dietary lipid sources had significant influences on growth performance and antioxidant capacity, as well as on lipid deposition. Low dietary 18:1n-9, high n-3 long-chain polyunsaturated fatty acids and an appropriate ratio of ALA/LNA (18,2n-6) could reduce lipid deposition in pompano tissues, especially liver.