Hachero-Cruzado Ismael, Rodriguez-Rua Ana, Torrent Ivana, Roman-Padilla Javier, Manchado Manuel
IFAPA Centro El Toruño, Junta de Andalucía, El Puerto de Santa María, Spain.
"Crecimiento Azul", Centro IFAPA El Toruño, Unidad Asociada al CSIC, El Puerto de Santa María, Spain.
Front Physiol. 2020 Sep 30;11:572545. doi: 10.3389/fphys.2020.572545. eCollection 2020.
Phospholipids (PL) are essential molecules for larval growth and development. In this study, growth, lipid metabolism and gene expression responses associated with different dietary PL levels in pelagic sole larvae were evaluated. In a first trial, the long-term effects on growth and survival of two experimental microdiets (MD) containing high (High-PL) or low (Low-PL) PL levels were tested and compared to a diet based on live prey (rotifers). The MD were supplied from 3 to 10 days post-hatch (dph) and from day 8 to 29 dph. High-PL fed larvae had higher dry mass (1.2-fold) than Low-PL fed larvae at 8 dph and both MD were smaller (2.9-fold) than larvae fed live preys. However, a compensatory growth (33% between 8 and 20 dph) occurred when MD were substituted by and by the end of the trial no significant differences in mass or survival occurred between the dietary treatments. In a second trial, growth, lipid metabolism and gene expression profiles of larvae fed with MD up to 8 dph were analyzed. Growth data confirmed that mass of larvae fed with High-PL was higher (1.3-fold) than the those fed Low-PL and they had lower levels of triacylglycerol (2.8-fold), cholesterol (1.2-fold) and cetoleic acid (1.7-fold). Histological analysis indicated an excess of lipid vacuoles in larvae fed with Low-PL and the expression analysis revealed a coordinated response to enhance lipid mobilization since the expression of genes involved in PL intermediate synthesis, PL remodeling as well as eight apolipoprotein was up-regulated. The down-regulation of apolipoprotein in larvae fed with Low-PL indicated a specific regulation by PL levels. The present work provides insight into the responses associated with dietary PL in early fish larvae, which will be of use for future studies aimed as designing effective larval sole diets.
磷脂（PL）是幼体生长和发育所必需的分子。在本研究中，评估了远洋鞋底幼体中与不同日粮PL水平相关的生长、脂质代谢和基因表达反应。在第一个试验中，测试了两种含有高（高PL）或低（低PL）PL水平的实验微饲料（MD）对生长和存活的长期影响，并与基于活饵（轮虫）的饲料进行了比较。MD在孵化后3至10天（dph）以及从第8天至29天供应。在8 dph时，高PL喂养的幼体比低PL喂养的幼体具有更高的干重（1.2倍），并且两种MD都比喂养活饵的幼体小（2.9倍）。然而，当用MD替代时发生了补偿性生长（8至20 dph之间为33%），并且在试验结束时，日粮处理之间在体重或存活方面没有显著差异。在第二个试验中，分析了喂养MD至8 dph的幼体的生长、脂质代谢和基因表达谱。生长数据证实，高PL喂养的幼体的体重高于低PL喂养的幼体（1.3倍），并且它们的三酰甘油水平较低（2.8倍）、胆固醇（1.2倍）和鲸蜡酸（1.7倍）。组织学分析表明，低PL喂养的幼体中存在过多的脂质空泡，并且表达分析显示，由于参与PL中间合成、PL重塑以及八种载脂蛋白的基因表达上调，对增强脂质动员有协调反应。低PL喂养的幼体中载脂蛋白的下调表明受PL水平的特定调节。本研究为早期鱼类幼体中与日粮PL相关的反应提供了见解，这将用于未来旨在设计有效的幼体鞋底日粮的研究。
