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.
Br J Nutr. 2013 Apr 28;109(8):1373-81. doi: 10.1017/S0007114512003418. Epub 2012 Aug 20.
Previous experiments with Senegalese sole (Solea senegalensis) have demonstrated that dietary lipid levels above 8% impaired growth and did not promote protein retention. We hypothesised that this low ability to use high-lipid diets may depend on the dietary protein level. In the present study, a 2 × 2 factorial design was applied where two dietary lipid (4-17% DM) and two dietary protein (below and above the requirement levels, 48 and 54% DM) levels were tested in juveniles for 114 d. Growth performance was not improved by the increase in dietary fat, irrespectively of the dietary protein levels. Protein retention was similar among the diets, although fish fed the diets with high lipid content resulted in significantly lower protein gain. Among the enzymes involved in amino acid catabolism, only aspartate aminotransferase activity in the liver was affected by the dietary lipid levels, being stimulated in fish fed high-lipid diets. Moreover, phosphofructokinase 1 activity was significantly elevated in the muscle of Senegalese sole fed 4% lipid diets, suggesting enhanced glycolysis in the muscle when the dietary lipid supply was limited and dietary starch increased. The results confirmed that high-lipid diets do not enhance growth, and data from the selected enzymes support the assumption that lipids are not efficiently used for energy production and protein sparing, even when dietary protein is below the protein requirement of the species. Furthermore, data suggest a significant role of glucose as the energy source in Senegalese sole.
先前的塞内加尔比目鱼（Solea senegalensis）实验表明，膳食脂肪水平高于 8%会损害生长，并且不会促进蛋白质保留。我们假设这种利用高脂肪饮食的能力较低可能取决于膳食蛋白质水平。在本研究中，采用了 2×2 析因设计，在 114 天的时间里，在幼鱼中测试了两种膳食脂肪（4-17%DM）和两种膳食蛋白质（低于和高于需求水平，48 和 54%DM）。无论膳食蛋白质水平如何，增加膳食脂肪都不能提高生长性能。蛋白质保留在不同的饮食之间相似，尽管摄食高脂肪含量饮食的鱼类的蛋白质获得量明显较低。在参与氨基酸分解代谢的酶中，只有肝脏中的天冬氨酸氨基转移酶活性受到膳食脂肪水平的影响，在摄食高脂肪饮食的鱼类中受到刺激。此外，4%脂肪饮食组中肌肉的磷酸果糖激酶 1 活性显著升高，表明当膳食脂肪供应有限且膳食淀粉增加时，肌肉中的糖酵解增强。研究结果证实，高脂肪饮食不能促进生长，并且从选择的酶的数据表明，即使在蛋白质低于该物种的蛋白质需求时，脂肪也不能有效地用于能量产生和蛋白质节约。此外，数据表明葡萄糖在塞内加尔比目鱼中作为能量来源的重要作用。
