CIMAR/CIIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental and ICBAS, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Rua dos Bragas, 289, 4050-123 Porto, Portugal.
Comp Biochem Physiol A Mol Integr Physiol. 2013 Sep;166(1):26-35. doi: 10.1016/j.cbpa.2013.05.007. Epub 2013 May 14.
Dietary lipids are the major energy source for metabolic purposes in most fish species, and improve dietary protein utilization for growth. In a previous study we have reported a low tolerance of Senegalese sole juveniles to dietary lipid levels and suggested a maximal dietary inclusion level of 8% lipids for both optimal growth and nutrient utilization. The mechanisms behind this apparent poor utilization of the dietary lipids are still to be elucidated. The primary aim of the present study was to investigate the overall process of digestion and lipid absorption in relation to dietary lipid levels. Triplicate groups of twenty fish (mean initial mass 29g) were fed two isonitrogenous diets (54% of protein dry matter basis) with different lipid levels (L4 and L17, 4 and 17% lipids dry matter basis), for 88days. Protein and lipid apparent digestibility coefficients as well as lipase activity were similar in both groups suggesting that Solea senegalensis has the ability to digest equally well a low fat or a high fat diet. Plasma triglyceride concentrations were significantly higher 5 and 16h after feeding in fish fed the L17 compared to those fed L4, following dietary lipid supply, demonstrating effective lipid absorption. Expression of proteins related to lipid transport (microsomal triglyceride transfer protein), trafficking (Fatty acid binding protein 11) and fatty acid uptake (VLDL-r) was significantly higher in liver of fish fed the high fat diet 16h after the meal, but remained unchanged in muscle. In conclusion, it seems that high fat diets do not impair lipid digestion and absorption.
饮食中的脂肪是大多数鱼类进行新陈代谢的主要能量来源，并且可以提高用于生长的膳食蛋白质利用率。在之前的研究中，我们报告了塞内加尔比目鱼幼鱼对饮食中脂肪水平的耐受性较低，并建议在最佳生长和营养利用方面，脂肪的最大饮食摄入量为 8%。这种饮食中脂肪利用率明显较差的机制仍有待阐明。本研究的主要目的是研究与饮食脂肪水平相关的消化和脂肪吸收的整体过程。三组二十只鱼（平均初始体重 29 克）分别喂食两种等氮饮食（54%的蛋白质干物质基础），脂肪水平不同（L4 和 L17，4%和 17%的脂肪干物质基础），共 88 天。两组的蛋白质和脂肪表观消化系数以及脂肪酶活性相似，表明塞内加尔比目鱼有能力很好地消化低脂肪或高脂肪饮食。与 L4 组相比，L17 组的鱼在喂食后 5 和 16 小时时，血浆甘油三酯浓度明显更高，这表明它们有效地吸收了脂肪。与脂肪转运（微粒体甘油三酯转移蛋白）、运输（脂肪酸结合蛋白 11）和脂肪酸摄取（VLDL-r）相关的蛋白质在高脂肪饮食组的肝脏中 16 小时后表达显著升高，但在肌肉中没有变化。总之，似乎高脂肪饮食不会损害脂肪消化和吸收。
