Transcriptomic and physiological analyses of hepatopancreas reveal the key metabolic changes in response to dietary copper level in Pacific white shrimp Litopenaeus vannamei

Abstract

All living organisms require copper for growth and development, but the gene expression profiles and molecular mechanisms underpinning dietary copper are poorly investigated. Therefore, the present study aimed to determine the potential metabolic changes in response to dietary copper based on analysis of hepatopancreas transcriptome in Litopenaeus vannamei. Three practical diets were formulated to supplement 0 (control diet; Csingle bondCu) and 40 mg kg−1 inorganic Cu (CuSO4·5H2O; Isingle bondCu) and copper amino acid chelate (Osingle bondCu), with analyzed Cu being 12.4, 49.8 and 50.0 mg kg−1, respectively. Shrimp fed Isingle bondCu and Osingle bondCu diets had higher percent weight gain and Cu concentration in tissues. Some essential amino acids (lysine, methionine, isoleucine, leucine, valine) and non-essential amino acids (tyrosine, glycine, aspartic acid, proline and serine) in hepatopancreas significantly increased in shrimp fed the copper supplemented diets. Transcriptome analysis indicated a total of 742 and 912 genes were differentially expressed (q < 0.001; log2fold change ≥2) in shrimp fed the Isingle bondCu and Osingle bondCu diets, respectively, in comparison to shrimp fed the control diet. Five and eight significantly changed pathways were annotated in the Csingle bondCu vs. Isingle bondCu and Csingle bondCu vs. Osingle bondCu comparisons, with metabolism the leading category for both. Similarly, the proportion of differentially expressed genes revealed that most were enriched in the category of metabolism. Further analysis revealed that dietary copper mainly affected amino acid and glycerophospholipid metabolism. Moreover, two significantly changed pathways (phagosome and IL-17 signaling pathway) related to the immune system were identified in shrimp fed the Osingle bondCu diet. The present study analyzing the hepatopancreas transcriptome identified potential roles of dietary copper on amino acid and glycerophospholipid metabolism and provided new insight that will be valuable in future studies to further elucidate the nutritional molecular basis of copper.