INTRODUCTION Fish inhabiting different aquatic habitats adapts to the environment by metabolomic readjustments. Understanding the combined activities of all the metabolic pathways (metabolome) helps in better understanding the complex interactions between gene and environment. OBJECTIVES The anadromous migratory Tenualosa ilisha is a high value food fish comprising the dominant fishery of the rivers Padma and Hooghly. The present study aimed at understanding the influence of the two habitats on the nutritional composition of hilsa. METHODS Metabolite profiling was carried out by GC/MS. De novo assembly of hilsa liver transcriptome was generated under Illumina HiSeq platform and multivariate analysis was employed for correlation and comparison. RESULTS GC/MS fingerprinting showed C16:0, C18:1, C20:5 and C22:6 to be the predominant fatty acids present in hilsa liver, which were also found to be significantly higher in Hooghly hilsa. Comparative transcriptome analysis revealed that the differentially expressed genes were mainly associated with 'lipid metabolism' and 'amino acid metabolism' pathways. Multivariate analysis between the metabolites amino acid, fatty acid and corresponding gene expression showed that few genes of amino acid metabolism (EZH1, ALAS2 and ALDH4A1) positively correlated with individual amino acids (lysine, glycine and glutamate) in Hooghly hilsa. Similarly, the key genes for LC-PUFA biosynthesis (ELOVL5, FADS2, CPT1) showed positive correlation with individual LC-PUFAs (C18:3, C20:4, C20:5, C22:6), indicating higher LC-PUFA biosynthesis potential in Hooghly hilsa. CONCLUSION Comparative metabolomic study in hilsa from the two different habitats showed that the habitats influence the nutritional composition as evidenced by high abundance of amino acids lysine, leucine and arginine and LC-PUFAs C18:3, C20:4, C20:5, C22:6 in Hooghly hilsa.

中文翻译：

---

为了更好地了解栖息地对营养成分的影响，对无节食的球状黄粉虫进行了比较代谢组学研究。

简介居住在不同水生生境中的鱼类通过代谢组学调整适应环境。了解所有代谢途径（代谢组）的综合活动有助于更好地了解基因与环境之间的复杂相互作用。目标适度迁徙的Tenualosa ilisha是一种高价值食用鱼，包括帕德玛河和Hooghly河的主要渔业。本研究旨在了解这两个栖息地对的营养成分的影响。方法通过GC / MS进行代谢物分析。在Illumina HiSeq平台上产生了hilsa肝转录组的从头组装，并采用多变量分析进行相关和比较。结果GC / MS指纹图谱显示C16：0，C18：1，C20：5和C22：6是hilsa肝脏中存在的主要脂肪酸，在Hooghly hilsa中也发现明显更高。比较转录组分析显示差异表达的基因主要与“脂质代谢”和“氨基酸代谢”途径有关。对代谢产物氨基酸，脂肪酸和相应基因表达的多变量分析表明，Hooghly hilsa中很少有氨基酸代谢基因（EZH1，ALAS2和ALDH4A1）与单个氨基酸（赖氨酸，甘氨酸和谷氨酸）呈正相关。同样，LC-PUFA生物合成的关键基因（ELOVL5，FADS2，CPT1）与单个LC-PUFA（C18：3，C20：4，C20：5，C22：6）显示正相关，表明更高的LC-PUFA生物合成潜力在Hooghly hilsa。