Dietary Carotenoids Influence Growth, Fillet Pigmentation, and Quality Characteristics of Black Sea Trout ( Salmo labrax Pallas, 1814)

This study was designed to evaluate the effects of carotenoid-containing diets on the culture characteristics, colour profile, and sensorial properties of Black Sea trout ( Salmo labrax ). Fish of approximately 300 g in weight were fed diets containing different levels of astaxanthin, canthaxanthin, and lycopene at 100 ppm, 200 ppm, and 300 ppm for 90 days. Ten feeding trials, including basal and carotenoid-containing diets, were run in an open-flow seawater aquaculture system at approximately 15 °C and 18‰ salinity. At the end of the trial, fish were harvested and measurements were performed. The final weight, meat yield, and condition factor were found to be higher in fish fed with astaxanthin and canthaxanthin than in the control group. The highest values were achieved with carotenoid supplementation at 300 ppm for 90 days in both groups. The lowest meat yield and condition factor were found in the fish fed with lycopene. The most effective pigmentation was achieved with 300 ppm astaxanthin at the end of the 90-day feeding trial with colour values of 61.34 L*, 29.84 a*, and 30.21 b*. In sensorial analyses, it was found that the most appreciated group in terms of both appearance and textural properties was the astaxanthin group, similarly to the results of colour measurements. Finally, carotenoid accumulation in the blood serum and fillets of Black Sea trout was determined and modelled with a Box-Behnken design via response surface methodology regarding carotenoid levels and feeding period. Graphic Abstract