Effects of Dietary Paprika and Lipid Levels on Growth and Skin Pigmentation of Pale Chub (Zacco platypus)

Two feeding experiments were conducted to investigate the effects of dietary paprika (DP) and lipid (DL) levels on growth performance and skin pigmentation of pale chub, Zacco platypus. Six diets (designated as $P_0L_8,\;P_0L_{17},\;P_8L_8,\;P_8L_{17},\;P_{16}L_8\;and\;P_{16}L_{17}$) were formulated to contain 0%, 8% and 16% paprika with 8% and 17% lipid, respectively. For the growth experiment (Exp I), three replicate groups of fish (average weight 2.6${\pm}$0.2 g) were fed one of the six experimental diets for 8 weeks. At the end of the feeding period, survival was above 94% and not significantly different among dietary treatments. Weight gain, feed efficiency and protein efficiency ratio of fish fed the $P_{16}L_8$ diet were lower than for fish fed the $P_0L_8$ diet. The highest total carotenoid (TC) content was observed in fish fed the $P_{16}L_8$ diet. For the pigmentation experiment (Exp II), each experimental diet was fed to two replicate groups of fish (average weight 9.0${\pm}$0.5 g) for 8 weeks. At the end of the feeding period, TC content of the skin was significantly affected by DP (p<0.05). The highest TC content of the skin was observed after 6 weeks of feeding at all dietary treatments. Astaxanthin content of the skin was not affected by DP and DL (p>0.05). The capxanthin and zeaxanthin contents of skin increased significantly with increasing DP, whereas the opposite trend was observed for lutein and ${\beta}$-cryptoxanthin contents. The skin lightness ($L^*$ values) significantly decreased whereas the values of $a^*$ and $b^*$ were significantly increased in fish fed the diets containing paprika (p<0.05). The present results suggest that feeding a diet containing 8% paprika and 8% lipid for 6 weeks could improve skin pigmentation of pale chub without any adverse effects on growth performance.