Dietary n-3 highly unsaturated fatty acids (HUFAs), which are low in vegetable oils (VO), are natural ligands of fatty acid-binding protein (fabp) genes, which function in molecular n-3 HUFAs metabolism in fish. Low water temperature (LWT) also affects fish fatty acid (FA) metabolism. Therefore, in this study, we investigated mRNA expression levels of fabp genes in European seabass (Dicentrarchus labrax) reared in LWTs. For this purpose, we cloned and characterized open reading frames of 10 fabp genes. Changes in the expression of fabp genes to VO-based diets for 60 days and fish oil (FO)-based diet for 30 days were determined. The present study's results suggest the following: (1) D. labrax fabp genes are orthologues of vertebrate fabp/FABP genes. (2) fabp1b.1/fabp1b.2 and fabp7a/fabp7b are retained in the D. labrax genome most likely because of the subfunctionalization. (3) The variation in tissue-specific expression of fabp10a/fabp10b and fabp11a/fabp11b paralogues also provides evidence of subfunctionalization; however, nutrigenomic results did not support this observation. Therefore, more detailed promoter analyses are needed to better understand their retentions in the D. labrax genome. (4) Feeding D. labrax with a FO-based diet following feeding with VO-based diets is insufficient for molecular FA metabolism recovery. This study is the first report on the characterization and nutritional regulation of fabp genes by dietary FAs in D. labrax reared in LWTs and suggests that transcriptional control of fabp genes by agonists would be helpful to maintain lipid homeostasis, protect fish health and increase fish welfare for sustainable aquaculture production.

中文翻译：

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低温养殖的欧洲海鲈 (Dicentrarchus labrax) 中植物油对脂肪酸结合蛋白 (fabp) 基因的鉴定、表征和营养调控

植物油 (VO) 含量低的膳食 n-3 高度不饱和脂肪酸 (HUFA) 是脂肪酸结合蛋白 ( fabp ) 基因的天然配体，在鱼类的分子 n-3 HUFA 代谢中发挥作用。低水温 (LWT) 也会影响鱼类脂肪酸 (FA) 的代谢。因此，在这项研究中，我们研究了在 LWT 中饲养的欧洲海鲈 ( Dicentrarchus labrax )中fabp基因的 mRNA 表达水平。为此，我们克隆并表征了 10 个fabp 基因的开放阅读框。确定了基于 VO 的饮食 60 天和基于鱼油 (FO) 的饮食 30 天的fabp基因表达的变化。本研究的结果表明：（1）D. labrax fabp基因是脊椎动物fabp/FABP基因的直系同源物。(2) fabp1b.1 / fabp1b.2和fabp7a / fabp7b保留在D. labrax基因组中很可能是因为亚功能化。(3) fabp10a / fabp10b和fabp11a / fabp11b旁系同源物组织特异性表达的变化也提供了亚功能化的证据；然而，营养基因组学结果并不支持这一观察结果。因此，需要更详细的启动子分析以更好地了解它们在D. labrax基因组中的保留。(4) 喂养D. labrax在喂食基于 VO 的饮食后采用基于 FO 的饮食不足以恢复分子 FA 代谢。这项研究是关于在LWT 中饲养的D. labrax中膳食 FAs对fabp基因的表征和营养调节的第一份报告，并表明激动剂对fabp基因的转录控制将有助于维持脂质稳态，保护鱼类健康和增加鱼类福利用于可持续水产养殖生产。