Abstract:

A feeding experiment was conducted to evaluate the effects of different levels of dietary carotenoid sources on growth, antioxidant responses, total carotenoid content, fatty acid profile and stress resistance of European seabass (Dicentrarchus labrax) with 0.3±0.02 g. Three types of carotenoids derived from either synthetic astaxanthin (AX; 0.05, 0.1 g kg-1), or natural source: marigold flower meal (ML; 0.1, 0.2, 0.3 g kg-1) and crab waste meal (CM; 5, 10, 15 g kg-1) were separately tested. The control diet (CTR) had no carotenoid supplementation. Nine fish treatments (three replicates each) were fed isonitrogenous (47% CP) and isolipidic (12.5%) diets three times per day to apparent satiation for 10 weeks. The study indicated that dietary supplementation with CM10 and ML0.2 exhibited better growth performance, weight gain, daily growth index and growth coefficient than the control group. After 10 weeks, total body carotenoids content significantly (P<0.05) increased with increasing supplemented levels AX, ML and CM in fish diets. Meanwhile, thiobarbituric acidreactive substances were significantly decreased in fish fed diets supplemented with high levels of carotenoid sources. Furthermore, carotenoids supplementation significantly improved fish resistance to thermal and salinity stress compared with control fish (P>0.05). Results have suggested that dietary inclusion of CM and ML at doses of 10 or 0.2 g kg-1 respectively, could improve growth, total carotenoid content, antioxidant activities and stress resistance of seabass fry as efficiently as the commercial synthetic astaxanthin.

Keywords: