Regulation of metabolism by dietary carbohydrates in two lines of rainbow trout divergently selected for muscle fat content
Regulation of metabolism by dietary carbohydrates in two lines of rainbow trout divergently selected for muscle fat content
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DOI：
10.1242/jeb.070581
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发表时间：
2012-08-01
影响因子：
2.8
通讯作者：
Panserat, Stephane
中科院分区：
文献类型：
--
作者：
Kamalam, Biju Sam;Medale, Francoise;Panserat, Stephane
先前对两种虹鳟鱼系的研究表明，它们在代谢葡萄糖的能力上存在差异，这两种虹鳟鱼系分别选择了瘦肉(L)或脂肪(F)肌肉。在这种情况下，我们研究了高肌肉脂肪含量的遗传选择是否会导致更好的膳食碳水化合物代谢能力。分别饲喂含或不含糊化淀粉（17.1%）的饲料10周，然后采集血液、肝脏、肌肉和脂肪组织。F系的生长率、饲料效率和蛋白质利用率低于L系。在这两项研究中，碳水化合物的摄入与中度餐后高血糖、蛋白质节约效应、营养（TOR-S6）信号级联的增强和能量感应酶（AMPK）的降低有关。饲喂碳水化合物的F系肝脏糖酵解酶基因表达量高于L系，但糖异生酶基因同时转录量也高于L系，这可能损害了葡萄糖稳态。然而，F系显示了与脂肪生成和脂肪酸生物转化有关的肝酶的较高基因表达，特别是随着饮食中碳水化合物摄入量的增加。增脂潜能的增强加上F系较高的肝糖原含量表明，F系比L系有更好的葡萄糖储存能力。总的来说，本研究证明了肝脏中间代谢的变化是由高肌肉脂肪含量和饮食碳水化合物摄入的遗传选择引起的，然而，与周围组织中改善生长或葡萄糖利用的任何相互作用无关。
Previous studies in two rainbow trout lines divergently selected for lean (L) or fat (F) muscle suggested that they differ in their ability to metabolise glucose. In this context, we investigated whether genetic selection for high muscle fat content led to a better capacity to metabolise dietary carbohydrates. Juvenile trout from the two lines were fed diets with or without gelatinised starch (17.1%) for 10 weeks, after which blood, liver, muscle and adipose tissues were sampled. Growth rate, feed efficiency and protein utilisation were lower in the F line than in the L line. In both lines, intake of carbohydrates was associated with a moderate postprandial hyperglycaemia, a protein sparing effect, an enhancement of nutrient (TOR-S6) signalling cascade and a decrease of energy-sensing enzyme (AMPK). Gene expression of hepatic glycolytic enzymes was higher in the F line fed carbohydrates compared with the L line, but concurrently transcripts for the gluconeogenic enzymes was also higher in the F line, possibly impairing glucose homeostasis. However, the F line showed a higher gene expression of hepatic enzymes involved in lipogenesis and fatty acid bioconversion, in particular with an increased dietary carbohydrate intake. Enhanced lipogenic potential coupled with higher liver glycogen content in the F line suggests better glucose storage ability than the L line. Overall, the present study demonstrates the changes in hepatic intermediary metabolism resulting from genetic selection for high muscle fat content and dietary carbohydrate intake without, however, any interaction for an improved growth or glucose utilisation in the peripheral tissues.