The effects of marigold (Tagetes erecta) and apo-ester on pigmentation of eletric yellow cichlid (Labidochromis caeruleus)

This study was carried out determine the effects on skin pigmentation and rearing parameters of electric yellow cichlid (Labidochromis caeruleus) fed diets containing 4% marigold (Tagetes erecta), 0 and 100 mg/kg synthetic apo-ester for 60 days. Skin colour was measured by colorimetric method using reflectance spectroscopy with transformation into colour parameters based on tristimulus values, L (lightness), a (redness) and b (yellowness). Effects of marigold and synthetic apo-ester on colour parameters of fish were similar (P>0.05). Both carotenoid sources provided higher b value in fish (P<0.05), but did not affect L and a value, compared to diets without carotenoids (P>0.05). On the other hand, carotenoid sources had no effect on growth performance, feed conversion ratio and survival rate of fish (P<0.05). This study demonstrate that marigold can be successfully used as an alternative natural carotenoid source to the synthetic apo-ester in electric yellow cichlid diets.