Differential effects of dietary copper deficiency and excess on lipid metabolism in yellow catfish Pelteobagrus fulvidraco

The present study was conducted to investigate the effects and mechanism of dietary Cu deficiency and excess on lipid metabolism in the liver, muscle and VAT of juvenile Pelteobagrus fulvidraco. To this end, yellow catfish were fed 0.76 (Cu deficiency), 4.18 (adequate Cu) and 92.45 (Cu excess) mg Cu kg(-1) diet, respectively, for 8 weeks.. WG and SGR in the adequate Cu group were significantly higher than those in Cu deficiency and excess groups. In liver, Cu deficiency showed no significant effect on Cu and lipid contents, the activities of 6PGD, G6PD and FAS, and the mRNA levels of many tested genes, including 6PGD, G6PD, FAS, ACC alpha, PPAR gamma, LXR, HSL, PPAR alpha and ATGL Cu excess induced Cu accumulation, reduced the lipid content, FAS activity as well as the mRNA levels of 6PGD, G6PD, FAS, ACC alpha, PPAR gamma, HSL and ATGL. In muscle, dietary Cu levels showed no significant effects on lipid content the activities of lipogenic enzymes and the mRNA levels of the most tested genes, including of 6PGD, G6PD, FAS, SREBP-1, PPAR gamma, HSL and LPL. In VAT, Cu and lipid contents, FAS activity, and the mRNA levels of 6PGD, G6PD, FAS, SREBP-1, LXR, PPARa and LPL were not significantly influenced by dietary Cu levels. Thus, the change of lipid contents among tissues could be related to the enzymatic activities and gene expression related to lipid metabolism. Different response patterns of enzymatic activities and gene expression in various tissues following dietary Cu levels indicated the tissue-specific regulatory effect by Cu. (C) 2015 Elsevier Inc All rights reserved.