Comparative Performance, Approximate Biochemical Composition and Consumer Preference of Albino and Normally Pigmented Varieties of Rainbow Trout (Oncorhynchus mykiss)

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 (8-18 degree C) under natural autumn -winter photoperiod (41 degree N) 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.