The pigmenting effect of different carotenoids on fancy carp (Cyprinus carpio)

The optimal concentration of a panel of individual and combined carotenoid sources on skin pigmentation in fancy carp was investigated by nine experimental diets that were formulated and supplemented with astaxanthin at 25 mg kg(-1), lutein at 25 and 50 mg kg(-1), beta-carotene at 25, 50 and 75 mg kg(-1), and lutein combined with b-carotene at 25 : 25 and 50 : 50 mg kg(-1), while a diet without supplemented carotenoid served as a control. The results showed that serum TC of fish fed diets containing supplemented with lutein plus b-carotene at 25 : 25; 50 : 50 mg kg(-1) and lutein 50 mg kg(-1) diet were higher than the other treatments (P <= 0.05). Serum TC of the respective treatments was 6.2 +/- 2.0, 7.8 +/- 3.3 and 7.3 +/- 1.9 lg mL(-1) serum, respectively. Fish fed diets combined with lutein and b-carotene at 25 : 25, 50 : 50 mg kg(-1) and lutein 50 mg kg(-1) diet had serum astaxanthin concentrations similar to fish fed the diet with astaxanthin alone at 25 mg kg(-1). Serum astaxanthin concentrations was 0.7 +/- 0.01, 0.9 +/- 0.01, 0.4 +/- 0.02 and 1.7 +/- 0.18 lg mL(-1) serum, respectively. The chromaticity of fish body skin of red and white position was assessed by colourimetry using the CIE L* a* b (CIELAB) system. Pigmentation response of skin redness of fancy carp fed with diets combined with lutein and beta-carotene at 25 : 25, 50 : 50 mg kg(-1) and lutein 50 mg kg(-1) were higher than other treatments (P <= 0.05) but they were similar to fish fed with 25 mg kg(-1) astaxanthin diet. The redness (a* values) of fish fed diets with diets combined with lutein and b-carotene at 25 : 25, 50 : 50 mg kg(-1) and lutein 50 mg kg(-1) were 28.3 +/- 0.53, 29.9 +/- 1.38, 28.8 +/- 3.95 and 28.5 +/- 2.49, respectively. After 3 weeks of feeding the experimental diets, the fish fed on a diet without carotenoid supplement for one week demonstrated that the same three groups still retained their redness and had an overall tendency to improve skin colouring. Finally, concentrations 50 mg kg(-1) of lutein, or the combination of lutein and b-carotene at 25 : 25 mg kg(-1) showed the highest efficiency for improving skin pigmentation and redness of skin.