摄食豆肽对星斑川鲽(Platichthys stellatus)幼鱼肝脏蛋白表达的影响

Effects of Soy Peptide on Protein Expression in Liver of Juvenile Starry Flounder (Platichthys stellatus)

关键词:  豆肽  双向电泳  肝脏蛋白  肝脏代谢  表达丰度

Key words:  Soy peptide  Two-dimensional electrophoresis  Hepatic protein  Hepatic metabolism  Expression abundance

摘要:

为揭示饲料中添加豆肽对星斑川鲽(Platichthys stellatus)幼鱼肝脏代谢产生的影响，利用大豆蛋白肽替代24%的鱼粉并以全鱼粉饲料为对照形成两种等氮等能的实验饲料，粗蛋白为(43.98±0.14)%、能量为(19.89±0.08) kJ/g。将240尾幼鱼分为两组，每组3个平行(40尾/桶)，分别投喂两种饲料50 d后，提取肝脏蛋白进行双向电泳并用PDQuest分析差异蛋白。结果显示，在pH 4−7、分子量14.4−97.4 kDa范围内，共检测到448−470个肝脏蛋白点，有14个蛋白的表达呈两倍以上的差异，其中3个为结构蛋白(中间纤维蛋白、II型细胞骨架8-样异构体X2、肌动蛋白)，其他11种肝脏蛋白参与不同代谢活动。以摄食全鱼粉饲料的肝脏蛋白为对照，幼鱼摄食豆肽饲料后明显上调了9种代谢蛋白和3种结构蛋白，下调了两种代谢蛋白。本研究结果表明，星斑川鲽幼鱼摄食豆肽饲料后其肝脏代谢发生变化，即提高高密度脂蛋白的生成，增强糖酵解、降低糖原合成从而使代谢向产能方向进行，降低胰蛋白酶的合成和提高应激蛋白的生成。本研究利用比较蛋白组学技术从肝脏蛋白表达的角度来揭示摄食豆肽对星斑川鲽幼鱼肝脏组织代谢的影响，为新型植物蛋白源的应用提供理论基础。

Abstract:

To investigate the effects of soy peptides on hepatic metabolism of juvenile starry flounder (Platichthys stellatus), two isonitrogenous (43.98±0.14% dry weight) and iso-energetic (19.89±0.08 kJ/g dry weight) experimental diets were formulated to contain 0% SPH (control, FM) and 24% SPH (SPH) respectively. Two hundred and forty juvenile starry flounders (initial weight of 5.73±0.36 g) were randomly distributed to 2 groups with three replicates per group (40 fish/replicate). Each group was fed one diet for 50 days before collecting liver samples for analysis. The results showed that 448−470 protein spots were detected in the gel area of pH 4−7 and Mr 14.4−97.4 kDa after 2-dimensional gel electrophoresis. Among them, fourteen hepatic proteins showed over 2-fold difference in expression abundance including 3 structural proteins (intermediate filament protein ON3-like, type II cytoskeletal 8-like isoform X2 and β-actin) and 11 proteins involved in different metabolism. Nine metabolic proteins and 3 structural proteins were up-regulated by at least 2-fold and other 2 metabolic proteins were decreased by 2-fold in fish fed SPH diet compared those fed FM diet. The present results revealed that SPH affected hepatic metabolism by enhancing synthesis of high density lipoprotein and stress protein, promoting glycolysis metabolism for energy production while reducing synthesis of trypsin. The present study elucidated the global metabolic response of fish liver to soy peptides using comparative proteomics technology and provides a theoretical basis to apply the novel plant proteins in aquatic feed.