Effect of pomegranate peel meal on the change in the fillet, blood and skin color of Rainbow trout (Oncorhynchus mykiss)

The main objective of this research was to study the effects of diets containing 1, 2, 3 and 4 percent pomegranate peel meal and also the control diet with no pomegranate peel meal, on the changes in carotenoid levels of fillet, blood and skin color of rainbow trout (Oncorhynchus mykiss). The experiment had a completely randomized design with four treatments, one control group and 3 replicates. Four hundred and fifty rainbow trout fish with a mean weight of 45 ± 5 g were divided into 15 small concrete canals. During a period of 60 days pomegranate peel meal was added to the fish diet, which had a significant effect on the carotenoid levels of fillet, blood and skin (P≤0.05) and subsequently the production of red color. Skin and fillet carotenoid concentrations were highest in treatments 1 and 3 with 1 and 3 percent added pomegranate peel meal (P≤0.05). Addition of 1 and 3 percent pomegranate peel meal had the best coloration in (3.33±0.01 & 3.28±0.07 mg/kg) fillet and skin respectively. The results showed that the blood carotenoids levels in treatments of 1 and 3 percent, were significantly higher than other treatments (P<0.05) and the lowest level (0/34±0/01 mg/l) was found in the control group.