Fish meal and fish oil are considered as the most nutritious and digestible ingredients for marine fish. The prices of both ingredients are higher than the other protein and lipid sources, such as soybean meal and corn gluten meal, and those have made downward trend of usage amount of fish meal and fish oil in aquaculture. The demand of those two ingredients has shown unbalanced conditions for the decades. According to the FAO, the disparity of supply and demand will continue to increase with the continuous worldwide growth of fish and livestock farming (FAO, 2016). Therefore, to lower the price of fish diet and to reduce the content of fish oil and fish meal in aquafeed, it is necessary to find out alternative sustainable dietary ingredients for aquaculture fish species.Plant protein sources were recommended by many authors and their cost seems cheaper and sustainable than fish meal. However, it is well-known that plant protein sources have issue with anti-nutritional factors and are lack of indispensable amino acid. It seems impossible Abstract 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 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. K E Y W O R D Salgae, DHA, feed source, fish feed, oil, red sea bream

Docosahexaenoic acid (DHA) is an essential fatty acid for marine carnivorous fish. Algal meal (AM), available as a new dietary DHA source, could completely replace dietary fish oil (FO). In this study, dietary FO was replaced with plant oil mixtures and AM in juvenile yellowtail Seriola quinqueradiata to investigate its effects on growth performance and fatty acid composition. The FO control diet was prepared with only pollack liver oil as the lipid source. For the non-FO diets, pollack liver oil was completely replaced with mixtures of canola oil and palm oil, with AM supplementation at 0% (AM0), 1% (AM1), 2% (AM2), 3% (AM3), and 4% (AM4). After completion of the 8-week feeding trial, the AM2 group showed significantly higher values for final body weight and feed efficiency than the AM0 group. No significant differences were observed in the other parameters of growth performance. Whole-body fatty acid composition reflected the dietary fatty acid composition in all dietary groups. These findings demonstrate that AM is useful as a DHA source in yellowtail aquaculture, thus contributing to a reduction in the use of FO in fish diets.

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For enhancing sustainability of aquaculture production, there have been many trials to replace fish-derived ingredient to other ingredients. Various plant protein sources (soybean, rape seed, sunflower, cotton seed, wheat, corn, peas, beans, peanut etc) and vegetable oils (soy bean, linseed, rapeseed, sunflower, palm oil, corn oil, echium and olive oil etc) were mainly considered as feed ingredients, However, most of them could not be the ideal source because of the major defects with imbalanced amino acid contents, anti-nutritional factor in plant protein sources and lack of omega 3 long-chain (C>20) poly unsaturated fatty acids (n-3 LC-PUFA) in vegetable oils (Francis

For developing sustainable fish feed in aquaculture industry, it has been indicated that minimizing fish-derived ingredient in aquaculture feed is important (Naylor et al., 2009). Plant protein and lipid sources are recommended as more stable and sustainable alternative feed ingredient than fish meal and oil; however, they are well-known for its demerits such as anti-nutritional factors, lack of indispensable amino acids and essential fatty acids for fish, low digestibility and palatability issues, poor growth performance in rearing trial (J.