Under-dimensioned hearts causing functional problems are associated with higher mortality rates in intensiveAtlantic salmon aquaculture. Previous studies have indicated that tetradecylthioacetic acid (TTA) induces cardiacgrowth and also stimulates transcription of peroxisome proliferator activated receptors (PPAR) ¿ and ß in theAtlantic salmon heart. Since cardiac and transcriptional responses to feed are of high interest in aquaculture, theobjective of this study was to characterize the transcriptional mechanisms induced by TTA in the heart of Atlanticsalmon.
Atlantic salmon were kept at sea for 17 weeks. During the first 8 weeks the fish received a TTA supplementeddiet. Using microarrays, profound transcriptional effects were observed in the heart at the end of the experiment,9 weeks after the feeding of TTA stopped. Approximately 90% of the significant genes were expressed higher inthe TTA group. Hypergeometric testing revealed the over-representation of 35 gene ontology terms in the TTAfed group. The GO terms were generally categorized into cardiac performance, lipid catabolism, glycolysis andTCA cycle.
Our results indicate that TTA has profound effects on cardiac performance based on results from microarray andqRT-PCR analysis. The gene expression profile favors a scenario of `physiological`lright hypertrophy recognizedby increased oxidative fatty acid metabolism, glycolysis and TCA cycle activity as well as cardiac growth andcontractility in the heart ventricle. Increased cardiac efficiency may offer significant benefits in the demandingAquaculture situations.