Molecular identification and tissue distribution of peroxisome proliferators activated receptor gamma transcript in cultured Thunnus orientalis

Pacific bluefin tuna (PBT) peroxisome proliferator‐activated receptor γ (PPARγ) gene was characterized to know the expression of its transcript contribution to the development of PBT, because PPARγ is the key molecule for adipose cell differentiation. Resulting cDNA and deduced amino acid sequence had high similarities to other teleosts that consisted of A to F domains. Phylogenetic tree analysis indicated a close relationship PBT PPARγ to cobia and flatfishes ones among the teleosts with the similarity of characteristic insertion sequences at amino terminal region of E/F domains. PPARγ transcripts quantification profile in the tissues of a 13‐month‐old PBT indicated the correlation between its quantity with the muscle types of different lipid content. The transcripts were also detected in the head kidney, digestive organs and red muscle with higher level inferred the PPARγ contribution to the multiple physiological processes. PPARγ transcripts were quantified for PBT juveniles fed artificial diets to investigate the effect of phospholipid supplementation on the growth, survival and PPARγ expression, to verify the efficacy of phospholipid source. No obvious difference in growth performance, survival and gene expression of PBT juveniles was identified, this may be due to DHA/EPA ratio analogy between diets and indicating that phospholipid sources in the juvenile diet might be adaptable.