Dietary n− 3 polyunsaturated fatty acids (PUFAs) have a role in preventing cardiovascular and hepatic diseases. However, their effects might differ significantly depending on individual dietary patterns. The aim of the present study was to evaluate the effects of dietary supplementation with ω-3 fatty acids (FA), administered in different schedules, on hepatic and aortic histological structure, lipid profile, and body weight (BW) in male Wistar rats under standard (SD), high-fat diet (HFD) and mixed feeding conditions. PUFA treatment consisted of the administration of 50 mg/kg fish oil (FO) daily by oral gavage. HFD was obtained by adding a suspension of 4% cholesterol, thiouracil and cholic acid to the animals’ drinking water. The rats were maintained on the diets for 6 weeks, and different schedules of PUFA administration were used. At 14, 28, and 42 days, the morphology of liver and aortic samples and the levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), and triglycerides (TG) were assessed. The HFD groups exhibited significant hyperlipidemia and aortic inflammation, with progression to atherogenesis after 6 weeks. Administration of PUFAs slightly attenuated the aortic changes in these groups and reduced the liver’s tendency to steatosis. FO-induced metabolic improvement was more evident in SD than in HFD rats. For instance, after the first 2 weeks, SD animals that received PUFAs had significantly increased HDL levels vs. controls (62.375 ± 4.10 vs. 52.625 ± 8.38 mg/dL, P < 0.05), but HFD rats did not, and decreased TG levels were observed exclusively in the SD rats (57.6 ± 4.09 vs. 66 ± 4.69 mg/dL, P < 0.05). After 6 weeks of n− 3 PUFA administration, LDL was significantly lower in the SD rats than in controls (13.67 ± 4.13 vs. 30.83 ± 2.86 mg/dL, P < 0.001), but the decrease in the HFD rats, although significant (49.17 ± 5.85 mg/dL vs. 57.17 ± 4.96 g/dL, P < 0.05), was not as marked. In the mixed-diet groups, administration of 50 mg/kg/day FO for 14 days under SD conditions following 4 weeks of HFD slightly decreased TG (86.625 ± 11.67 vs. 73 ± 4.52 mg/dL, P < 0.05) and increased HDL (45.875 ± 5.28 vs. 56 ± 3.16 mg/dL). However, in these animals, n-3 PUFA administration had no effect on LDL or TC. Administration of half of the above dose failed to improve any biochemical parameters. FO protected against excessive weight gain mainly under SD conditions. The results show that FO confers more protection against cardiovascular risk factors (increased LDL and TG, decreased HDL) and liver lipid accumulation when given to rats consuming regular diets than when given to rats consuming a high-fat diet. This argues that priority should be given to consumption of a healthy diet rather than to the use of supplements. The effectiveness of n-3 PUFAs might be reduced in the case of hyperlipidic intake or after consumption of a high-fat diet.

中文翻译：

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在大鼠饮食中添加鱼油后，在常规喂养条件下，血清脂质和肝脏形态的改善比在高脂肪或混合饮食下更为明显。

膳食中的 n−3 多不饱和脂肪酸 (PUFA) 具有预防心血管和肝脏疾病的作用。然而，根据个人饮食模式，它们的效果可能会有很大差异。本研究的目的是评估膳食补充 ω-3 脂肪酸 (FA)（以不同的时间表给药）对雄性 Wistar 大鼠的肝脏和主动脉组织学结构、血脂谱和体重 (BW) 的影响。标准（SD）、高脂饮食（HFD）和混合喂养条件。PUFA 治疗包括每天口服 50 mg/kg 鱼油 (FO)。HFD是通过在动物的饮用水中添加4%胆固醇、硫尿嘧啶和胆酸的悬浮液而获得的。大鼠维持饮食6周，并采用不同的PUFA给药方案。第14、28和42天时，检测肝脏和主动脉样本的形态以及总胆固醇（TC）、高密度脂蛋白胆固醇（HDL）、低密度脂蛋白胆固醇（LDL）和甘油三酯（TG）的水平。评估。HFD 组表现出明显的高脂血症和主动脉炎症，并在 6 周后进展为动脉粥样硬化。多不饱和脂肪酸的施用略微减弱了这些组中的主动脉变化，并降低了肝脏脂肪变性的倾向。FO 诱导的代谢改善在 SD 大鼠中比在 HFD 大鼠中更明显。例如，前两周后，接受 PUFA 的 SD 动物与对照组相比，HDL 水平显着升高（62.375 ± 4.10 vs. 52.625 ± 8.38 mg/dL，P < 0.05），但 HFD 大鼠没有这种情况，并且 TG 水平降低仅在 SD 大鼠中观察到（57.6 ± 4.09 vs. 66 ± 4.69 mg/dL，P < 0.05）。给予 n−3 PUFA 6 周后，SD 大鼠的 LDL 显着低于对照组（13.67 ± 4.13 vs. 30.83 ± 2.86 mg/dL，P < 0.001），但 HFD 大鼠的降低虽然显着（ 49.17 ± 5.85 mg/dL vs. 57.17 ± 4.96 g/dL，P < 0.05），未如标记的那样。在混合饮食组中，在 HFD 4 周后，在 SD 条件下施用 50 mg/kg/天 FO 14 天，TG 略有下降（86.625 ± 11.67 vs. 73 ± 4.52 mg/dL，P < 0.05），HDL 增加（45.875 ± 5.28 与 56 ± 3.16 毫克/分升）。然而，在这些动物中，n-3 PUFA 给药对 LDL 或 TC 没有影响。施用上述剂量的一半未能改善任何生化参数。FO 主要在 SD 条件下防止体重过度增加。结果表明，与摄入高脂肪饮食的大鼠相比，给予常规饮食的大鼠 FO 可以更好地预防心血管危险因素（LDL 和 TG 增加，HDL 降低）和肝脏脂质积累。这表明应优先考虑健康饮食而不是使用补充剂。在高脂摄入或食用高脂肪饮食后，n-3 PUFA 的功效可能会降低。