Dietary copper improves growth and regulates energy generation by mediating lipolysis and autophagy in hepatopancreas of Pacific white shrimp (Litopenaeus vannamei)

Abstract

Copper is an essential micronutrient for living organisms, but its biological function has not been sufficiently studied, especially in crustaceans. Therefore, the present study aimed to evaluate the role of copper in the maintenance of energy homeostasis by mediating lipid and energy metabolism in Litopenaeus vannamei. L. vannamei (initial weight 0.90 ± 0.00 g) were fed diets containing 12.4 (Cu12.4), 22.0 (Cu22.0), 31.0 (Cu31.0), 41.7 (Cu41.7) and 49.8 (Cu49.8) mg kg−1 Cu for 8 weeks. Lipid and energy metabolism-related biochemical and molecular parameters were determined, and ultrastructural observation performed in hepatopancreas. Growth performance, tissue Cu deposition, antioxidant parameters, and expression of genes involved in Cu homeostasis and autophagy were also evaluated. Dietary copper supplementation improved growth, Cu concentration in tissue, and antioxidant capacity compared to the Cu-deficient diet. Copper promoted lipolysis and β-oxidation, confirmed by elevated expression levels of cpt1, ampkγ, acbp, acadl, acadm, acadvl, acox1, acox3 and decreased expression of srebp, acc1, 6pgd, and markedly increased activities of LPS and CPT1 and decreased ACC activity. Expression levels of genes related to autophagy (atg13, atg3, atg12, atg9, beclin1) were up-regulated, and autolysosomes and autophagosome were observed in the hepatopancreas of shrimp fed diets supplemented with copper. Furthermore, energy metabolism related parameters (ATPase, cytochrome c oxidase, citrate synthase, adenosine 5′-triphosphate) and genes involved in tricarboxylic-acid cycle (cs, aco, idh, ogdh, sdhc, sdhd, fh, mdh) were up-regulated in shrimp fed copper supplemented diets. The present study showed that copper-mediated lipolysis and autophagy can coordinate energy generation, and provided new insight into copper nutrition and the potential beneficial effects of dietary Cu on energy metabolism in crustaceans.