PIGMENTATION OF RAINBOW-TROUT (ONCORHYNCHUS-MYKISS) WITH CAROTENOIDS FROM RED-PEPPER

In this study, the effects of synthetic astaxanthin and red pepper on the pigmentation of rainbow trout Oncorhynchus mykiss were investigate d. The fish (167 g) were fed three diets: Diet A (control diet with no addition of carotenoids), Diet B (75 mg/kg synthetic astaxanthin adde d) and Diet C (5% red pepper supplemented) for 20, 40 and 60 days. Reg ardless of the experimental period the highest and lowest total carote noid deposition in the fillet of the fish were found in fish fed Diet B (8.12 mg/kg) and Diet A (0.62 mg/kg), respectively (p<0.05). The die t containing red pepper (Diet C) gave a significantly higher carotenoi d concentration (5.66 mg/kg) than the control but a lower level than t he diet containing astaxanthin (p<0.05). However, the live weight gain of the groups did not differ significantly (p>0.05). Addition of 75 m g/kg astaxanthin (Diet B) increased the total cost of the feed by 15%, whereas addition of 5% red pepper (Diet C) to obtain 75 mg/kg of tota l carotenoid increased the cost by 14%.