Effect of bee pollen extract as a source of natural carotenoids on the growth performance and pigmentation of rainbow trout (Oncorhynchus mykiss)

Abstract

In this study, carotenoids were extracted from bee pollen using sunflower oil as a solvent, and the extract was incorporated into pellets for trout feeding. A total of 144 rainbow trout were fed over eight weeks using pellets with added bee pollen extract. The following diets (treatments) were used: (1) negative control (C−) without carotenoids; (2) positive control (C+) with synthetic astaxanthin (50 mg kg−1); (3) pollen extract with carotenoids (25 mg kg−1) (P1); and (4) pollen extract with carotenoids (50 mg kg−1) (P2). At the end of eight weeks, there were no significant differences between treatments regarding the total growth parameters (p > .05). However, the P2 diet had a positive effect on periodical measurements of growth parameters. Trout fed with treatment P1 exhibited the lowest (p < .05) average vicerasomatic index (8.80 ± 0.31%). Instrumental color analysis showed that fillets of trout fed with treatment C+ had higher (p < .05) pigmentation intensities than those fed with the other diets. Fillets of trout fed with treatments P1 or P2 had a higher (p < .05) carotenoid concentration and a paler pink color than those fed with a diet that did not have added carotenoids (C−).