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Two feeding experiments were conducted to develop non‐fish meal and non‐fish oil diet for yellowtail with plant protein sources and Schizochytrium meal. For the first experiment, three iso‐nitrogenous and iso‐lipidic diets were prepared. Control diet was composed with fishmeal and fish oil and the other diet was formulated with plant protein sources and fish oil [FO]. Fish oil in FO diet was totally substituted by rapeseed oil and Schizochytrium sp., which was rich in DHA [NFO1]. Duplicate groups of yellowtails (Seriola quinqueradiata, 190.6 g) were fed the diets for 99 days. NFO1 group showed the lowest palatability and growth. However, fatty acid profile of NFO1 group showed the similar trend to FO. Four non‐fish meal diets were prepared for the second experiment with increased amount of feed attractant. 100FO diet was formulated similar to FO diet in the first experiment though higher amount of bonito peptide was contained. The other diets gradually employed Schizochytrium meal to substitute fish oil in 100FO diet for 35, 70 and 100%, respectively [65FO, 30FO, NFO2]. Duplicated groups of yellowtails (186.0 g) were fed the diets for 84 days. The growth result was improved by increasement of bonito peptide; however, it was inversely proportional to employment rate of algae meal. The results suggest possibility for developing non‐fish meal diet for yellowtail with plant protein sources and Schizochytrium sp. by inducing enough amount of feed attractant. Moreover, it needs further study on essential fatty acid utilization for yellowtail while developing non‐fish meal and non‐fish oil diet with microalgae. [ABSTRACT FROM AUTHOR]

A feeding experiment was conducted to develop non‐fish meal and non‐fish oil diet for red seabream by using plant protein source and Schizochytrium meal which is rich in 22:6n‐3 (DHA). Three iso‐nitrogenous and iso‐lipidic experimental diets were prepared (CP 41.2% ± 0.4%, CL 16.4% ± 1%). Control diet contained both fish meal (40%) and fish oil (6%). In the second diet, fish meal was replaced by plant meals (soy protein concentrate, soybean meal, corn gluten meal) [FO]. In the third diet, fish meal and fish oil were replaced by algae meal (Schizochytrium sp. powder) and plant proteins [AO]. Duplicated groups of juvenile red seabream (8.8 g ± 1.5) were fed the experimental diets for 12 weeks to near satiation. There was no statistical difference among treatment in specific growth rate. Feed conversion ratio of AO diet group was higher than that of control. In wet basis, whole body protein level was significantly higher in AO diet than FO group while lipid content was lower than control group. In fatty acid profile, AO group had significantly lower 18:4n‐3, 20:4n‐3, 22:5n‐3 and 20:5n‐3 (EPA) level, but significantly higher 18:3n‐3 and DHA level than the other two diet fed fish. The results might suggest that further developments in microalgae diet offer a promising lipid source of n‐3 PUFA as essential fatty acid on marine fish. And it showed possibility to develop non‐fish meal and non‐fish oil feed for marine aquaculture fish by using microalgae. [ABSTRACT FROM AUTHOR]