32 DECEMBER 2014 • WORLD AQUACULTURE • WWW.WAS.ORG (Willey et al. 2003) and striped bass Morone saxitilis (Harel et al. 2001). The essential fatty acid requirements for optimal growth of the Japanese eel were satisfied by n-3 and n-6 PUFA (Takeuchi et al. 1980). Additionally, we investigated the optimum levels of dietary n-3 or n-6 fatty acids and the availability of AA in elver and juvenile stages of Japanese eel (Bae 2003, Bae et al. 2004). In our experiment, the WG, FE and SGR of fish were significantly influenced by dietary ARA level. WG and FE of fish fed ARA0.8 and ARA1.2 diets were significantly greater than that of fish fed ARA0.07, ARA0.22 and ARA0.43 diets; there were no significant differences among fish fed ARA0.6, ARA0.8 and ARA1.2 diets. Castell et al. (1994) and Bell et al. (1995) demonstrated that dietary ARA promotes growth of juvenile turbot and concluded that ARA is an essential fatty acid for juvenile turbot. These studies provided the first evidence that ARA is an essential fatty acid for normal growth, development and survival of juvenile marine fish. In addition, Koven et al. (2001) suggested the importance of dietary ARA for improving resistance to handling stress in gilthead sea bream larvae. The authors proposed that increased prostaglandin E2 (PGE2) production in the ARA supplemented fish was responsible for up-regulation of cortisol synthesis through the hypothalamus-pituitary interrenal axis, resulting in improved response to acute stress (Bell and Sargent 2003). On the other hand, it has been reported that high levels of ARA in the diet negatively affect growth and survival of the larvae of cod (Zheng et al. 1996), Japanese flounder (Furuita et al. 1998) and yellowtail (Ishizaki et al. 1998). Likewise, in our study, the best growth and feed utilization effects were observed in the fish fed an optimum ARA level in the diet. In the present study, the dietary arachidonic acid (ARA) requirement for the juvenile eel, A. japonica based on WG and SGR was 0.69-0.71 percent of the diet (Fig. 5). Conclusion As it is unlikely that capture fisheries production of Japanese eel will increase further, substantial investment and multilateral efforts are warranted to boost aquaculture production to meet the ever-increasing demand for this species. A clear understanding of the optimum level of macro- and micro-nutrients is imperative to formulate nutritionally balanced and cost-effective diets for Japanese eel. Based on a series of experiments conducted in our laboratory with different age groups, vitamin C requirement is equal to or greater than 41.1 mg/kg diet, vitamin E requirement is >21.2 but <21.6 mg/kg diet and arachidonic acid requirement is 0.69-0.71 percent of the diet. Notes Sungchul C. Bai, Department of Marine Biomaterials & Aquaculture, Feeds and Foods Nutrition Research Center, Pukyong National University, Busan 608-737, Korea (Rep.) scbai@pknu.ac.kr Kumar Katya and Hyeonho Yun, Department of Marine Biomaterials and Aquaculture, Feeds and Foods Nutrition Research Center, Pukyong National University, Busan 608-737, Korea (Rep.) References Ai, Q., K. Mai, B. Tan, W. Xu, W. Zhang, H. Ma and Z. Liufu. 2006. Effects of dietary vitamin C on survival, growth and immunity of large yellow croaker, Pseudosciaena crocea. Aquaculture 242:489-500. Al-Amoundi, A.A., A.M.N. El-Nakkadi and B.M. El-Nouman. 1992. Evaluation of optimum dietary requirement of vitamin C for the growth of Oreochromis sprilurus fingerlings in water from the Red Sea. Aquaculture 105:165-173. Bae, J.Y. 2003. Studies on requirements of optimum dietary essential fatty acids in eel, Anguilla japonica. M.S. Thesis, Department of Fisheries Biology, Pukyong National University, Busan, Korea. Bae, J.Y., K.M. 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