CIMAR/CCMAR, Universidade do Algarve, Campus de Gambelas, Faro, Portugal.
Mar Biotechnol (NY). 2012 Oct;14(5):643-54. doi: 10.1007/s10126-012-9462-3. Epub 2012 May 13.
Lysine (Lys) is an indispensable amino acid (AA) and generally the first limiting AA in vegetable protein sources in fish feeds. Inadequate dietary Lys availability may limit protein synthesis, accretion and growth of fish. This experiment aimed to further elucidate the role of Lys imbalance on growth by examining the myotomal muscle proteome of juvenile zebrafish (Danio rerio). Quadruplicate groups of 8 fish were fed either a low-Lys [Lys(-), 1.34 g kg(-1)], medium/control (Lys, 2.47 g kg(-1)) or high-Lys [Lys(+), 4.63 g kg(-1)] diet. Fish growth was monitored from 33 to 49 days post-fertilization (dpf) and trunk myotomal muscle proteome of Lys(-) and Lys(+) treatments were screened by 2D-DIGE and MALDI ToF tandem mass spectrometry. Growth rate was negatively affected by diet Lys(-). Out of 527 ± 11 (mean ± S.E.M.) protein spots detected (∼10-150 kDa and 4-7 pI value), 30 were over-expressed and 22 under-expressed in Lys(-) fish (|fold-change| >1.2, p value <0.05). Higher myosin light chains abundance and other myofibrillar proteins in Lys(-) fish pointed to increased sarcomeric degradation, indicating a higher protein turnover for supplying basal energy-saving metabolism rather than growth and muscle protein accretion. The Lys deficiency also possibly induced a higher feeding activity, reflected in the over-expression of beta enolase and mitochondrial ATP synthase. Contrarily, in the faster growing fish [Lys(+)], over-expression of apolipoprotein A-I, F-actin capping protein and Pdlim7 point to increased energy storage as fat and enhanced muscle growth, particularly by mosaic hyperplasia. Thus using an exploratory approach, this study pinpoints interesting candidates for further elucidating the role of dietary Lys on growth of juvenile fish.
赖氨酸（Lys）是一种必需氨基酸（AA），通常是鱼类饲料中植物蛋白源的第一限制氨基酸。日粮中 Lys 供应不足可能会限制蛋白质的合成、积累和鱼类的生长。本实验旨在通过检查斑马鱼（Danio rerio）幼鱼的肌节肌肉蛋白质组，进一步阐明 Lys 失衡对生长的作用。将 4 组 8 条鱼分别饲喂低 Lys [Lys(-)，1.34 g kg(-1)]、中/对照（Lys，2.47 g kg(-1)]或高 Lys [Lys(+)，4.63 g kg(-1)]日粮。从受精后 33 天到 49 天（dpf）监测鱼的生长情况，并通过 2D-DIGE 和 MALDI ToF 串联质谱筛选 Lys(-)和 Lys(+)处理的 trunk 肌节肌肉蛋白质组。日粮 Lys(-)对生长速度有负面影响。在检测到的 527 ± 11（平均值 ± S.E.M.）个蛋白质点（约 10-150 kDa 和 4-7 pI 值）中，30 个在 Lys(-)鱼中过表达，22 个在 Lys(-)鱼中低表达（|fold-change| >1.2，p 值 <0.05）。Lys(-)鱼中肌球蛋白轻链丰度和其他肌原纤维蛋白的增加表明肌节降解增加，表明为了提供基础的节能代谢而不是生长和肌肉蛋白积累，蛋白质周转率更高。Lys 缺乏还可能导致更高的摄食活动，这反映在 beta 烯醇酶和线粒体 ATP 合酶的过表达上。相反，在生长较快的鱼[Lys(+)中，载脂蛋白 A-I、F-肌动蛋白盖帽蛋白和 Pdlim7 的过表达表明能量以脂肪的形式储存增加，并增强了肌肉生长，特别是通过镶嵌性增生。因此，本研究采用探索性方法，确定了有趣的候选基因，以进一步阐明日粮 Lys 对幼鱼生长的作用。
