Effects of a diet supplemented with Japanese grape (Hovenia dulcis) seed oil on the omega-3 and nutritional lipid quality in Nile tilapia (Oreochromis niloticus)

Abstract

In this study, the fatty acid (FA) composition of the Japanese grape (Hovenia dulcis) seed oil (JGSO) was firstly evaluated. It was found that the seed oil is rich in alpha-linolenic acid (LNA), containing approximately 425 mg LNA g-1 of total lipids. A fish diet supplemented with JGSO was prepared and supplied to Nile tilapia to investigate the FA composition of the fillets. For this, Nile tilapia were submitted to two feeding treatments: a control diet with 4.2% of soybean oil, and a diet supplemented with 4.2% of JGSO. The LNA, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) values increased significantly (406, 153 and 126%, respectively) with JGSO in the diet and with an increase in feeding time, while the nutritional quality indexes, n-6/n-3 ratio and index of thrombogenicity, decreased 2.8 and 1.4 times, respectively. Thus, the replacement JGSO in the diet raised the nutritional lipid quality in Nile tilapia.