عنوان مقاله [English]
This study investigated effect of the partial and total replacement of astaxanthin with carrot powder (0, 25, 50, 75 and 100%) on the carotenoid content of the skin, fillet and blood of rainbow trout (Oncorhynchus mykiss). Therefore, a completely randomized design with 5 treatments and one control group, each with 3 replications, was designed. A total of 300 fish with an average initial weight of 50.00±30 g were divided into 18 experimental fiberglass ponds. The experiment period was 60 days. The results showed that addition of the carrot powder to diet had a significant effect on the carotenoid level of the skin, fillets and blood of fish, resulting in red color. Carotenoid concentration of the skin and fillet increased significantly by adding carrot powder to diet (P<0.05). Addition of 50 and 75% of the carrot powder as a natural pigment resulted in the highest amount of the carotenoid storage in the tissue and skin (0.40413±0.029 and 0.0240-0.001 mg/kg) and had a significant difference with other treatments (P<0.05). The results showed that Carrot's carotinoids were significantly higher in treatments of 50 and 75% than others (P<0.05) and the lowest level (0.0269±0.30 mg/kg) was observed in the control group.