Growth rates, daily feed consumption (FC), feed conversion rates (FCR), condition factor (CF), tissue compositions and consumer preference of albino (A), and normally pigmented (N) varieties of rainbow trout (Oncorhynchus mykiss) were examined by rearing them in all albino, all normal and mixed or duo-culture groups. The fish were held at ambient water temperatures (8-180C) under natural autumn - winter photoperiod (410N) and fed manually for 7 days a week, and twice a day to apparent satiation. At the end of the 122 day trial period the mean weights of the groups reached 317.5+66.03 g (normal), 366.4+74.27 g (duo normal), 315.3+44.63 g (duo albino) and 319.9+50.26 g (albino). Statistical analysis of the final weight values showed that only the normally pigmented fish in duo-culture exhibited significantly higher growth. There were no significant variations in other variables examined. However, the feed conversion ratio in the duo-culture seemed to be slightly better than the others. Consumer preferences were in favour of the normal pigmented fish. It has been concluded that the colour genes controlling the albino phenotype may have pleiotropic effects on growth only in duo- or mixed culture of two varieties.
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Alanärä, A. 1992. Demand feeding as a self-regulating feeding system for rainbow trout (Oncorhynchus mykiss) in net-pens. Aquaculture, 108: 347-356.
Bondari, K. 1984. Comparative of albino and normal pigmented channel catfish in tanks, cages and ponds. Aquaculture, 37: 293-301.
Bridges, W.R. and von Limbach. 1972. Inheritance of albinism in rainbow trout. The Journal of Heredity, 63: 152-153.
Cho, C.Y. 1992. Feeding systems for rainbow trout and other salmonids with reference to current estimates of energy and protein requirements. Aquaculture, 100: 17-123.
Dobosz, S., Kohlmann, K., Goryczko, K. and Kuzminski, H. 1999. Growth and vitality in yellow forms of rainbow trout. Journal of Applied Ichthyology, 16 (3): 117-120
Holm, J.C., Refstie, T. and Bø, S. 1990. The effect of fish density and feeding regimes on individual growth rate and mortality in rainbow trout (Oncorhynchus mykiss). Aquaculture, 89: 225-232.
Holtby, L.B., Swain, D.P. and Allan, G.M. 1993. Mirror- elicited agonistic behaviour and body morphology as predictors of dominance status in juvenile coho salmon (Oncorhynchus kisutch). Canadian Journal of Fisheries and Aquatic Sciences, 50: 676-684.
Jobling, M. 1985. Physiological and social constraints on growth of fish with special reference to Arctic charr, Salvelinus alpinus L. Aquaculture, 44: 83-90.
Jobling, M. 1995. Feeding of charr in relation to aquaculture. Nordic J. Freshw. Res., 71: 102-112.
Jobling, M., Arnesen, A.M., Baardvik, B.M., Christiansen, J.S. and Jørgensen, E.H. 1995. Monitoring feeding behaviour and food intake: Methods and applications. Aquaculture Nutrition, 1: 131-143.
Johansen, S.J.S. and Jobling, M. 1998. The influence of feeding regime on growth and slaughter traits of cage- reared Atlantic salmon. Aquaculture International, 6: 1-17.
Johansson, L., Kiessling, A., Åsgård, T. and Berglund, L. 1995. Effects of ration level in rainbow trout, Oncorhynchus mykiss (Walbaum), on sensory characteristics, lipid content and fatty acid composition. Aquaculture Nutrition, 1: 59-66.
Jørgensen, E.H., Christiansen, J.S. and Jobling, M. 1993. Effects of stocking density on food intake, growth performance and oxygen consumption in Arctic charr (Salvelinus alpinus). Aquaculture, 10: 191-204.
Keenleyside, M.H.A. and Yamamoto, F. T. 1962. Territorial behaviour of juvenile Atlantic salmon (Salmo salar L.). Behaviour, 19: 139-169.
Kirpichnikov, V.S. 1981. Genetic Base of Fish Selection. Springer, Berlin, 410 pp.
O’Keefe, R.A. and Benfey, T.J. 1997. The feeding response of diploid and triploid Atlantic salmon and brook trout. Journal of Fish Biology, 51: 989-997.
Okumuş, İ., Çelikkale, M.S., Kurtoglu, İ.Z. and Başçınar, N. 1999. Saf ve karışık olarak yetiştirilen gökkuşağı (Oncorhynchus mykiss) ve kaynak (Salvelinus fontinalis) alabalıklarının büyüme performansları, yem tüketimi ve yem değerlendirme oranları. Turkish Journal of Veterinary and Animal Sciences, 23: 123- 130.
Rothbard, S. and Wohlfarth, G.W. 1993. Inheritance of albinism in the grass carp, Ctenopharyngodon idella. Aquaculture, 115: 13-17.
Storebakken, T., Hung, S.S.O., Calvert, C.C. and Plisetskaya, E.M. 1991. Nutrient partitioning in rainbow trout at different feeding rates. Aquaculture, 96: 191-203.
Tave, D. 1993. Genetics for Fish Hatchery Managers. 2nd edition, Van Nostrand Reinhold, New York, 415+ix pp.
Thorgaard, G.H., Spruell, P., Wheeler, P.A., Scheerer, P.A., Peek, A.S., Valentine, J.J. and Hilton, B. 1995. Inicidence of albinos as monitor for induced triploidy in rainbow trout. Aquaculture, 137: 121-130.