Microarray Analysis of Hepatic Gene Expression in Juvenile Japanese Flounder Paralichthys olivaceus Fed Diets Supplemented with Fish or Vegetable Oils

Abstract

Gene expression profiling was performed in Japanese flounder Paralichthys olivaceus fed diets supplemented with fish oil (FO), linseed oil (LO), or olive oil (OO) for 6 weeks. The LO and OO groups showed significantly retarded growth, lower feed intake, lower protein efficiency ratio, and lower hepatosomatic index (P < 0.05). Liver fatty acid composition reflected the dietary fatty acid composition. Microarray analysis revealed that dietary n - 3 highly unsaturated fatty acid (HUFA) deficiency affected 169 transcripts. In the LO group, 57 genes were up-regulated and 38 genes were down-regulated, whereas in the OO group nine genes were up-regulated and 87 genes were down-regulated. Analysis of the functional annotations suggested that dietary n - 3 HUFA affected genes involved in signal transduction (23.2 %), cellular processes (21.1 %), metabolism (including glucose, lipid, and nucleobase; 15.5 %), transport (11.3 %), regulation of transcription (10.5 %), and immune response (4.2 %). Several genes encoding serine/threonine kinases such as protein kinase C and calmodulin-dependent kinase and nuclear hormone receptors such as vitamin D receptor, retinoic acid receptor, and receptors for cytokines (bone morphogenic protein and transforming growth factor β) were affected. Among 169 transcripts, 22 genes were affected in both LO and OO groups. The present study identified several genes involved in n - 3 HUFA deficiency-sensitive pathways, which will be useful for selective breeding of flounder strains able to adapt to n - 3 HUFA deficiency.

Replacement of Marine Fish Oil with de novo Omega‐3 Oils from Transgenic Camelina sativa in Feeds for Gilthead Sea Bream (Sparus aurata L.)

“…Up-regulation in srebp1 expression in liver was observed in fish fed the three VO in agreement with studies carried out in elovl5 −/− mice that indicated low levels of EPA and DHA lead to activation of this transcription factor [55]. Similar results have been obtained in other fish species when fed low levels of n-3 LC-PUFA or VO [50, 56–58]. Up-regulation of srebp1 in VO-fed fish could lead to the regulation of srebp1 target genes such as fads2 , hl , lpl , cpt1a and cpt1b .…”

Cloning and characterization of SREBP-1 and PPAR-α in Japanese seabass Lateolabrax japonicus, and their gene expressions in response to different dietary fatty acid profiles

“…This result provided a new evidence for the involvement of SREBP-1 in the regulation of fish Fad by dietary fatty acids. Studies on Japanese flounder and Atlantic salmon also showed that fish fed diets supplemented with vegetable oils had higher gene expression levels of SREBP-1 compared with fish fed diets supplemented with fish oil (Morais et al, 2011;Limtipsuntorn et al, 2014). In mammal, it has been well known that SREBP-1 in particular SREBP-1c activity can be inhibited by PUFA such as α-linolenic acid (18:3n−3), γ-linolenic acid (18:3n−6), ARA (20:4n−6), EPA (20:5n−3), and DHA (22:6n−3) (Deng et al, 2002;Yoshikawa et al, 2002;Sekiya et al, 2003;Jump et al, 2005Jump et al, , 2008Espenshade, 2006;Leaver et al, 2008;Lecker et al, 2011;Lee and Song, 2012;Fukumitsu et al, 2013).…”

A nutritionally-enhanced oil from transgenic Camelina sativa effectively replaces fish oil as a source of eicosapentaenoic acid for fish

“…Dietary impacts on metabolism were determined by investigating the transcriptome of liver as the main organ integrating, processing and distributing dietary lipid 47 . Several studies analysing fish transcriptomic responses after substitution of dietary fish oil with vegetable oils have shown that, regardless of oil employed, metabolism and in particular lipid metabolism, are highly affected categories 47 48 49 50 51 For instance, genes involved in LC-PUFA biosynthesis were overrepresented among the DEG in liver of Atlantic salmon fed vegetable oils 47 . In the present study, this applies to fish fed both WCO and ECO diets, where these genes occupy the top positions among the 100 highest expressed genes in terms of intensity, when compared to fish fed FO.…”