Terova Genciana, Robaina Lidia, Izquierdo Marisol, Cattaneo Annagiulia, Molinari Silvia, Bernardini Giovanni, Saroglia Marco
Department of Biotechnology and Life Sciences, University of Insubria, Via J.H. Dunant, 3 - 21100, Varese, Italy ; Inter-University Centre for Research in Protein Biotechnologies "The Protein Factory"- Polytechnic University of Milan and University of Insubria, Varese, Italy.
Springerplus. 2013 Dec;2(1):17. doi: 10.1186/2193-1801-2-17. Epub 2013 Jan 19.
The expression and regulation of intestinal oligopeptide transporter (PepT)-1 when vegetable sources are used as a substitute for fish meal in the diet of marine fish has not yet been explored. In the present study, as part of our ongoing work on elucidating PepT1 gene expression in relation to different dietary treatments, we have now isolated and deposited in Genbank database (accession no. GU733710) a cDNA sequence representing the PepT1 in the sea bream (Sparus aurata). The "de novo" prediction of the three-dimensional structure of PepT1 protein is presented.We also analyzed diet-induced changes in the expression of PepT1 mRNA via real-time RT-PCR using the standard curve method. Sea bream were fed for 140 days with one of the following four diet formulations (43% protein/21% lipid): a control fast growth-promoting diet (C), and three diets with the same formulation but in which 15% of the fish meal was substituted by protein concentrates either from lupine (LPC), chick pea (CPC), or green pea (PPC). Fish fed PPC had significantly (p < 0.05) lower levels of PepT1 transcripts in the proximal intestine than the controls, whereas PepT1 transcript levels in fish fed LPC or CPC were not significantly different from the controls. Although growth was similar between fish fed with different diets during the first 72 days of feeding, growth of the fish fed with PPC was reduced during the second part of the trial and was significantly (p < 0.05) lower than fish fed LPC and CPC diets by the end of the experiment. Correlation between these results and fish growth performances highlights that the intestinal PepT1 mRNA level may serve as a useful marker of the dietary protein quality and absorption efficiency.
在海水鱼饲料中使用植物源替代鱼粉时，肠道寡肽转运体（PepT）-1的表达及调控尚未得到研究。在本研究中，作为我们正在进行的关于阐明PepT1基因表达与不同日粮处理关系工作的一部分，我们现已分离出代表黑鲷（Sparus aurata）PepT1的cDNA序列，并将其存入Genbank数据库（登录号GU733710）。文中呈现了PepT1蛋白三维结构的“从头”预测。我们还通过实时RT-PCR使用标准曲线法分析了日粮诱导的PepT1 mRNA表达变化。用以下四种日粮配方（43%蛋白质/21%脂肪）之一喂养黑鲷140天：对照快速生长促进日粮（C），以及三种配方相同但其中15%鱼粉被来自羽扇豆（LPC）、鹰嘴豆（CPC）或绿豌豆（PPC）的蛋白质浓缩物替代的日粮。喂食PPC的鱼近端肠道中PepT1转录本水平显著（p < 0.05）低于对照组，而喂食LPC或CPC的鱼PepT1转录本水平与对照组无显著差异。尽管在喂养的前72天不同日粮喂养的鱼生长相似，但在试验的第二阶段喂食PPC的鱼生长减缓，到实验结束时显著（p < 0.05）低于喂食LPC和CPC日粮的鱼。这些结果与鱼生长性能之间的相关性突出表明，肠道PepT1 mRNA水平可能作为日粮蛋白质质量和吸收效率的有用指标。
