Coastal nursery areas are subjected to a wide range of natural and anthropogenic stressors, including global warming, which indirectly influence trophic food webs. A global rarefaction of n-3 polyunsaturated fatty acids (PUFA) in trophic networks is in progress. The aim of this study was to assess the effect of a reduction in the dietary availability of n-3 PUFA on some molecular and biochemical parameters related to lipid metabolism and oxidative stress response in juvenile European sea bass (Dicentrarchus labrax) raised at two temperatures (15 °C and 20 °C). Fish were fed for five months with a reference diet (RD; 1.65% n-3 PUFA on a dry matter basis, DM), used as a proxy of trophic networks where n-3 PUFA is plentiful, and a lower n-3 PUFA diet (LD; 0.73% n-3 PUFA DM), designed to mimic a decrease in n-3 PUFA resulting from global changes (the n-3 PUFA levels tested remained above the nutritional minimum required for this species). Results showed that diet did not affect the hepatic expression of some mRNA coding for transcriptional factors involved in regulating the metabolic pathways related to fatty acid bioconversion. Although our molecular analysis was limited to transcript expression, these data suggest the presence of a threshold in the nutritional supply of PUFA above which the activation of these molecular pathways does not occur. However, the expression for most of the transcripts tested was up-regulated at 20 °C. Despite the high peroxidation index in fish fed RD, very few modifications of the oxidative stress response were associated with diet. At 20 °C, an increase of the enzymatic antioxidant response was observed, but there was no correlation with the peroxidation index or malondialdehyde products.

中文翻译：

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热量和营养条件对欧洲鲈鱼（Dicentrarchus labrax）幼鱼脂肪酸代谢和氧化应激反应的影响

沿海育苗区受到各种自然和人为压力因素的影响，包括全球变暖，这会间接影响营养食物网。营养网络中 n-3 多不饱和脂肪酸 (PUFA) 的全球稀化正在进行中。本研究的目的是评估在两种温度下饲养的欧洲鲈鱼幼鱼（Dicentrarchus labrax）中，膳食中 n-3 多不饱和脂肪酸的减少对与脂质代谢和氧化应激反应相关的一些分子和生化参数的影响。 15 °C 和 20 °C）。用参考饮食（RD；1.65% n-3 PUFA，以干物质为基础，DM）喂鱼五个月，用作营养网络的代理，其中 n-3 PUFA 丰富，而 n-3 PUFA 较低饮食（LD；0.73% n-3 PUFA DM），旨在模拟全球变化导致的 n-3 PUFA 减少（测试的 n-3 PUFA 水平仍高于该物种所需的最低营养水平）。结果表明，饮食不影响一些编码转录因子的 mRNA 的表达，这些转录因子参与调节与脂肪酸生物转化相关的代谢途径。虽然我们的分子分析仅限于转录表达，但这些数据表明 PUFA 的营养供应存在阈值，高于该阈值不会发生这些分子途径的激活。然而，大多数测试的转录本的表达在 20°C 时上调。尽管喂食 RD 的鱼的过氧化指数很高，但氧化应激反应的改变很少与饮食有关。在 20 °C 时，