Effects of dietary lipid levels on growth and carotenoid accumulation of freshwater fish cichlid Labidochromis caeruleus
FU Xu, CUI Qianjin, CHEN Bing, YANG Boxue, CAI Zhonglu, WANG Xu, LIU Xia, JIANG Zhiqiang, HAN Yuzhe*
Key Laboratory of Mariculture & Stock Enhancement in North China’s Sea, Ministry of Agriculture and Rural Affairs, Liaoning Key Laboratory of Fish Applied Biology and Aquaculture in North China, Dalian Ocean University
Abstract: One hundred and twenty healthy cichlid Labidochromis caeruleus juveniles with initial body weight of (1.70 g±0.09 g) were reared 15 tanks and fed 200 g/kg xanthophyll containing diets supplemented with 0% (as control), 7.44%(Z1), 9.86%(Z2), 10.91%(Z3), 15.25%(Z4) and 23.69%(Z5) of lipid prepared by addition of soya bean oil at rate of 0, 30, 60, 92, and 100 g/kg at water temperature of 25.0 ℃ for 68 days to investigate the effect of dietary lipid levels on growth, pigmentation and carotenoid accumulation of cichlid. The maximal final body weight and specific growth rate were found in cichlid in group Z3, significantly higher than those in Z1 (P<0.05), with lower food conversion ratio in Z3 than that in other groups with the maximal and survival rate in groups Z3 and Z4. The survival rate was significantly lower in group Z5 than that in other groups (P<0.05). There was slight increase in viscera-somatic ratio with increase in dietary lipid levels, without significant difference(P>0.05). However, hepato-somatic index were shown to be significantly lower in groups Z3 and Z4 than that in other groups (P<0.05). Cichlid in group Z3 had significantly higher condition factor than the fish in other groups did (P<0.05). The content of total tissue carotenoid was increased with the increase in dietary lipid levels, without significant difference in brightness (L*) among the groups (P>0.05). However, yellowness (b*) was found to be increased first and then decreased and redness (a*) was found to be increased, with prolongation of the feeding trial, especially the brightness, redness and yellowness at different sampling points in the same treatment group. Cichlid had increase in activity of liver alanine aminotransferase, significantly higher in group Z5 than that in Z1 (P<0.05). It is recommended that 10.76% of dietary lipid level be proper for cichlid , that inappropriate dietary lipid level may not only affect growth but also negatively alter fish pigmentation.
付旭, 崔前进, 陈冰, 杨博学, 蔡忠璐, 王旭, 刘霞, 姜志强, 韩雨哲. 饲料脂肪水平对淡黑镊丽鱼生长及色素蓄积的影响[J]. 大连海洋大学学报, 2020, 35(1): 56-62.
FU Xu, CUI Qianjin, CHEN Bing, YANG Boxue, CAI Zhonglu, WANG Xu, LIU Xia, JIANG Zhiqiang, HAN Yuzhe. Effects of dietary lipid levels on growth and carotenoid accumulation of freshwater fish cichlid Labidochromis caeruleus. Journal of Dalian Ocean University, 2020, 35(1): 56-62.
2020, Vol. 35 
