Hepatic transcriptome of the euryhaline teleost Japanese seabass (Lateolabrax japonicus) fed diets characterized by α-linolenic acid or linoleic acid

To investigate the different effects of dietary alpha-linolenic acid (ALA) and linoleic acid (LA) on the euryhaline fish Japanese seabass, a feeding trial followed by hepatic transcriptome assay was conducted. Two experimental diets containing 10% LA-rich sunflower seed oil (diet LA) or 10% ALA-rich perilla oil (diet ALA) were used in the feeding trial. LA and ALA in diets were characteristically incorporated into fish tissues while no significant difference was observed in growth performance and body proximate composition between groups LA and ALA. Compared to LA, ALA up-regulated transcription of 49 unigenes and down-regulated those of 311 unigenes. Quantitative RT-PCR studies on eight lipid metabolism-related genes and seven randomly selected genes were conducted to validate the transcriptomic results. Lipid metabolism-related genes ApoA1, ApoA4, ApoE, FABP1, FABP3, FABP4, FATP6, and DGAT1, as well as ribosomal proteins L9e, L13e, and S4e, were transcriptionally down-regulated by ALA. The differentially expressed genes (DEGs) were primarily enriched in Gene Ontology terms such as Lipid transport, Protein metabolic process, and Ribosome biogenesis, as well as in KEGG pathways such as Complement and coagulation cascades and Ribosome. The Protein-Protein Interaction (PPI) network based on the peptide biosynthesis-related DEGs showed that ribosomal proteins such as SAe, L4e, S4e, L15e, L9e, and L13Ae had high betweenness centrality in the dietary regulation of peptide biosynthetic processes. In conclusion, under the present experimental conditions, a high level of dietary alpha-linolenic acid tended to suppress lipid transport and protein biosynthetic processes in the liver of Japanese seabass at the gene expression level.