This study investigated the effects of adding different amounts of a-tocopherol acetate (ATA, 100, 300 and 500 mg kg"1 diet), to a commercial feed on the growth performance, body composition and vitamin E levels in the fillet of rainbow trout (initial weight = 131.3 ±1.0 g) over a period of 58 days. In the analyses of trial diets, average rates of 46.6 ±0.4% crude protein, 13.9+0.1% lipid, and 130.2 (Diet 1), 370.5 (Diet 2) and 580.9 (Diet 3) mg kg"1 diet of vitamin E were found, respectively. The results of the 58-day feeding study were that the specific growth rate and condition factors of the fish were not affected by diets containing different levels of ATA (P>0.05). Fish that were fed 370.5 and 580.9 mg $kg^{-1}$ ATA diets had significantly lower feed conversion ratios than fish that were fed a 130.2 mg kg"1 ATA diet (P<0.05). The diets containing different levels of ATA did not affect the fillet's proximate composition, viscerosomatic index, or hepatosomatic index, except for the fillet and liver lipid content. The fillet and liver lipid content and hepatosomatic index of the fish increased with growth. The vitamin E levels in fish fillet reflected dietary ATA levels. The increase in dietary ATA affected ATA accumulation in the fish fillets and whole-body lipids. The high level of ATA in the fish flesh indicated good flesh quality. These results showed that fish on Diets 2 and 3 had significantly better FCR than those on Diet 1, and fish on Diet 3 had significantly higher flesh quality than the others.
___
Akhtar, P., Gray, J.I., Cooper, T.H., Garling, D.L. and Booren, AM. 1999. Dietary pigmentation and deposition of a-tocopherol and carotenoids in rainbow trout muscle and liver tissue. Journal of Food Science, 64 (2): 234-239.
Anonymous. 2001. Food and agriculture organization (FAO). Fishery information, data and statistics service. Aquaculture production, 2000. Fishstat plus, www.fao.org.
AOAC (Association of Official Analytical Chemists). 1998. Official Methods of Analysis (16th. Edition). Gaithersburg, Maryland, 20877-2417 USA. Vols. I, and II, 4th Revision.
Bai, S.C. and Gatlin, D.M. 1993. Dietary vitamin E concentration and duration of feeding affect tissue ot-tocopherol concentrations of channel catfish {Ictalurus punctatus). Aquaculture, 113: 129-135.
Bai, S.C. and Lee, K.J. 1998. Different levels of dietary DL-a-tocopheryl acetate affect the vitamin E status of juvenile Korean rockfish, Sebastes schlegeli. Aquaculture, 161: 405-414.
Baker, R.T.M. 1997. The effect of dietary a-tocopherol and oxidized lipid on post-thaw drip from catfish muscle. Animal Feed Science Technology, 65: 35-43.
Boggio, S.M., Hardy, R.W., Babbitt, J.K. and Brannon, E.L. 1985. The influence of dietary lipid source and alpha toeopheryl acetate level on product quality of rainbow trout (Salmo gairdneri). Aquaculture, 51:13-24.
Chaiyapechara, S., Casten, M.T., Hardy, R.W. and Dong, F.M. 2003. Fish performance, fillet characteristics, and health assessment index of rainbow trout (Oncorhynchus mykiss) fed diets containing adequate and high concentrations of lipid and vitamin E. Aquaculture, 219: 715-738.
Frigg, M., Prabucki, A.L. and Ruhdel, E.U. 1990. Effect of dietary vitamin E levels on oxidative stability of trout fillets. Aquaculture, 187: 105-125.
Gatta, P.P, Pirini, M., Testi, S., Vignola, G. and Monetti, P.G. 2000. The influence of different levels of dietary vitamin E on sea bass Dicentrarchus labrax flesh quality. Aquaculture Nutrition, 6: 47-52.
Halver, J.E. 1972. Fish Nutrition. Academic Press. London, 713 pp.
Hamre, K., Berge, R.K. and Lie, 0. 1998. Oxidative stability of Atlantic salmon (Salmo salar, L.) fillet enriched in a-, y-, and 8-tocopherol through dietary supplementation. Food Chemistry, 62 (2): 173-178.
Huang, C.H., Chang, R.J., Huang, S.L. and Chen, W. 2003. Dietary vitamin E supplementation affects tissue lipid peroxidation of hybrid tilapia, Oreochromis niloticus X O. aureus. Comp. Biochem. and Physiol. Part B, 134: 265-270.
Huo, J.Z., Nelis, H.J., Lavens, P., Sorgeloos, P. and De Leenheer, A.P. 1999. Simultaneous determination of a-tocopheryl acetate and tocopherols in aquatic organisms and fish feed. Journal of Chromatography B, 724: 249-255.
Huo, J.Z., Nelis, H.J., Lavens, P., Sorgeloos, P. and Leenheer, A. 1996. Determination of vitamin E in aquatic, organisms by high performance liquid chromatography with fluorescence detection. Anal. Biochem., 242: 123-128.
Jensen, C, Birk, E., Jokumsen, A., Skibsted, L.H. and Bertelsen, G. 1998. Effect of dietary levels of fat, a-tocopherol and astaxanthin on colour and lipid oxidation during storage of frozen rainbow trout (Oncorhynchus mykiss) and during chill storage of smoked trout. Zeitschrift fur Lebensmittel Unters. Forsch. A, 207:189-196.
Jobling, M., Koskela, J. and Salvolainen, R. 1998. Influence of dietary fat level and increased adiposity on growth and fat deposition in rainbow trout, Oncorhynchus mykiss (Walbaum). Aquaculture Research, 29: 601-607.
Kaushik, S.J., Gouillou-Coustans, M.F. and Cho, C.Y. 1998. Application of the recommendations on vitamin requirements of finfish by NRC (1993) to salmonids and sea bass using practical and purified diets. Aquaculture, 161: 463-474.
Köprücü, K. and Özdemir, Y. 2002. The contents of A2, C and E vitamins in the meat of rainbow trout {Oncorhynchus mykiss Walbaum, 1792). F.Ü. Fen ve Mühendislik Bilimleri Dergisi, 14 (2): 227-232.
Lie, 0. 2001. Flesh quality - the role of nutrition. Aquaculture Research, 32(1): 341-348.
Lim, P.K., Boey, P.L. and Ng, W.K. 2001. Dietary palm oil level affects growth performance, protein retention and tissue vitamin E concentration of African catfish, Clarias gariepinus. Aquaculture, 202: 101-112.
Lindhorst-Emme, W. 1990. Forellenzucht. Bedarf, Produktion, Werbung, Absatz. Verlag Paul Parey, Hamburg und Berlin, 157pp.
Lygren, B., Hamre, K. and Waagbo, R. 2000. Effect of induced hyperoxia on the antioxidant status of Atlantic salmon Salmo salar L., fed three different levels of dietary vitamin E. Aquacultur Research, 31: 401-407.
Ng, W.K., Lim, P.K. and Boey, P.L. 2003. Dietary lipid and palm oil source affects growth, fatty acid composition and muscle a-tocopherol concentration of African catfish, Clarias gariepinus. Aquaculture, 215: 229-243.
Nickell, D.C. and Bromage, N.R. 1998. Effect of dietary lipid level on variation of flesh pigmentation in rainbow trout (Oncorhynchus mykiss). Aquaculture, 161:237-251.
NRC (National Research Council). 1993. Nutrient requirements of fish. National Academy Press, Washinton, Dc, USA, 114pp.
Pirini, M., Gatta, P.P., Testi, S., Trigari, G. and Monetti, P.G. 2000. Effect of refrigerated storage on muscle lipid quality of sea bass (Dicentrarchus labrax) fed on diets containing different levels of vitamin E. Food Chemistry, 68: 289-293.
Rasmussen, R.S., Ostenfeld, T.H., Ronsholdt, B. and McLean, E. 2000. Manipulation of end-product quality of rainbow trout with finishing diets. Aquaculture Nutrition, 6: 17-23.
Ricker, W.E. 1979. Growth Rates and Models. W.S Hoar, D.J. Randall and J.R. Brett Eds. Fish Physiology, Vol.8. Academic Press, New York.
Ruff, N., FitzGerald, R.D., Cross, T.F., Hamre, K. and Kerry, J.P. 2003. The effect of dietary vitamin E and C level on market-size turbot (Scophthalmus maximus) fillet quality. Aquaculture Nutrition, 9: 91-103.
Ruff, N., FitzGerald, R.D., Cross, T.F., Teurtrie, G. and Kerry, J.P. 2002. Slaughtering method and dietary a-tocopheryl acetate supplementation affect rigor motris and fillet shelf-life of turbot Scophthalmus maximus L. Aquaculture Research, 33: 703-714.
Scaife, J.R., Onibi, G.E., Murray, I., Fletcher, T.C. and Houlihan, D.F. 2000. Influence of a-tocopherol acetate on the short-and long-term storage properties of fillets from Atlantic salmon Salmo salar fed a high lipid diet. Aquaculture Nutrition, 6: 65-71.
Weatherup, R.N. and McCracken, K.J. 1999. Changes in rainbow trout, Oncorhynchus mykiss (Walbaum), body composition with weight. Aquaculture Research, 30:305-307.
Zar, J.H. 1984. Biostatistical Analysis. Prentice-Hall, Englewood Cliffs, NJ, 718 pp.