This study was designed to evaluate the effect of dietary lipid levels on the mRNA transcripts of lipid metabolic regulatory genes. Nine combinations of experimental diets containing graded lipid (80, 100, and 120 g/kg) and protein (450, 500, and 550 g/kg) levels were fed to the Clarias magur (Indian walking catfish) larvae from 14 to 35 dph (day post hatching). All the lipolytic genes, such as pancreatic triacylglycerol lipase (PL), lipoprotein lipase (LPL), and bile salt-activated lipase (BAL), and genes for long-chain polyunsaturated fatty acid (LC-PUFA) biosynthetic enzymes like fatty acyl desaturase-2 (FADS2), fatty acyl desaturase-5 (FADS5), and elongase (ELOV) were expressed in a wide range of tissues. A high abundance of mRNA transcript levels of lipolytic genes was detected in the intestine and liver, and similarly, desaturases and elongase were predominantly found to be expressed in the liver, brain, and intestine. Among the diets, a significantly high expression of both lipolytic and LC-PUFA biosynthetic genes were observed at 8% dietary lipid level. The mRNA expression of all the studied genes was down-regulated at 12% dietary lipid contents. Hence, the present study concludes that the efficient nutrient utilization and the lipid metabolic pathway occur at the optimum dietary lipid level of 8% in C. magur larvae.

中文翻译：

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用分级脂质水平喂养的鲶鱼幼体中脂肪分解和长链脂肪酸生物合成基因的表达谱

本研究旨在评估膳食脂质水平对脂质代谢调节基因 mRNA 转录的影响。将含有分级脂质（80、100 和 120 克/千克）和蛋白质（450、500 和 550 克/千克）水平的九种实验饮食组合喂给 14 至 35 dph 的 Clarias magur（印度步行鲶鱼）幼虫（孵化后的一天）。所有脂肪分解基因，如胰三酰甘油脂肪酶 (PL)、脂蛋白脂肪酶 (LPL) 和胆汁盐活化脂肪酶 (BAL)，以及长链多不饱和脂肪酸 (LC-PUFA) 生物合成酶基因，如脂肪酰基去饱和酶-2 (FADS2)、脂肪酰基去饱和酶-5 (FADS5) 和延长酶 (ELOV) 在多种组织中表达。在肠道和肝脏中检测到高丰度的脂解基因 mRNA 转录水平，类似地，去饱和酶和延长酶主要在肝、脑和肠中表达。在饮食中，在 8% 的饮食脂质水平下观察到脂肪分解和 LC-PUFA 生物合成基因的显着高表达。所有研究基因的 mRNA 表达在饮食脂质含量为 12% 时下调。因此，本研究得出的结论是，C. magur 幼虫的有效营养利用和脂质代谢途径发生在 8% 的最佳膳食脂质水平。