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| DHA营养强化对半滑舌鳎仔鱼脂肪酸代谢模式和DNA甲基化修饰的影响 |
| Effects of DHA nutrition programming on fatty acid metabolism and DNA methylation patterns in larvae of Cynoglossus semilaevis |
| 投稿时间：2025-02-17 修订日期：2025-03-31 |
| DOI： |
| 中文关键词: 营养强化、半滑舌鳎、DNA甲基化、脂肪酸代谢、仔稚鱼 |
| 英文关键词: Nutrition programming Cynoglossus semilaevis DNA methylation Fatty acid metabolism Larvae |
| 基金项目:山东省重点研发计划(2021SFGC0701)、烟台市海珍品质量安全控制与精深加工重点实验室开放基金(QSCDP202311)共同资助。 |
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| 中文摘要: |
| 为优化半滑舌鳎品质,探索表观遗传调控长链高不饱和脂肪酸(LC-HUFA)合成机制,本试验研究了二十二碳六烯酸(DHA)营养强化对半滑舌鳎仔稚鱼生存能力、脂肪酸沉积及表观遗传修饰调控脂肪酸代谢的影响,为养成优质半滑舌鳎鱼种提供理论基础。使用DHA强化剂对孵育中的卤虫进行强化,以强化卤虫开口仔鱼作为试验组,同时以未强化卤虫开口仔鱼作为对照组,养殖至开口后15天(15dph)进行取样,统计孵化率、存活率、畸形率及体长,检测稚鱼全鱼脂肪酸组成及脂肪酸代谢基因表达,分析fads2基因DNA甲基化修饰状态。结果显示:15dph时,试验组存活率及体长显著提高,畸形率显著降低(P<0.05)；亚油酸(LA)、花生四烯酸(ARA)、亚麻酸(LNA)和DHA含量显著升高,n-6多不饱和脂肪酸(PUFA)和n-3PUFA含量显著升高(P<0.05)；pparα、acc1和fas基因表达量显著降低,fads2和fabp1表达量显著升高,elovlα基因表达量无显著性差异(P>0.05)；距离fads2转录起始位点-750bp至-1050bp存在一个CpG岛,片段总长度为301bp,共有8个候选CpG位点,其中5个CpG位点发生显著去甲基化修饰(P<0.05),从总体甲基化水平来看,fads2启动子区域存在高度去甲基化修饰现象(P<0.05)。本试验使用DHA对半滑舌鳎仔鱼进行营养强化可提高稚鱼生存能力,通过促进脂肪酸转运和去饱和作用提高稚鱼鱼体LC-HUFA合成,从而改善脂肪酸代谢模式,同时发现早期营养强化参与fads2启动子区域去甲基化修饰,从而提高fads2基因转录表达。本研究有助于养成半滑舌鳎高LC-HUFA优质仔稚鱼,为半滑舌鳎高效养殖提供新思路。 |
| 英文摘要: |
| Lipid is the second largest nutrient source of fish, plays an important role in the nutrient metabolism. As the essential fatty acid, the main component of lipid, long chain highly unsaturated fatty acids (LC-HUFA) plays an important role on regulating metabolism and maintaining cell morphology. The synthesis of LC-HUFA involves many biological processes such as fatty acid transport, de novo synthesis, β-oxidation, desaturation, and carbon chain elongation. A stable LC-HUFA metabolic pattern has been formed through long-term evolution. Previous studies have shown that exogenous intake can increase LC-HUFA accumulation and regulate metabolism in juvenile fish, however, there are few studies on larvae. Early nutritional programming can affect the metabolic of the body, accompanied by epigenetic regulation at times. There are a great significance to explore how to activate LC-HUFA synthesis limitation by early nutrition programming in fish, and further regulated by epigenetic mechanisms. The study explored the effects of docosahexaenoic acid (DHA) nutrition programming on the viability, fatty acid deposition and epigenetic modification of fatty acid metabolism in larvae of Cynoglossus semilaevis to provide a theoretical basis for the development of high-quality fish of Cynoglossus semilaevis. Hatchling of Artemia salina was fortified with DHA fortifier. Larvae of Cynoglossus semilaevis feed with fortified Artemia salina was used as the experimental group, and feed with unfortified Artemia salina was used as the control group. The larvae was cultured for 15 days post hatching (15dph), and the hatching rate, survival rate, malformation rate and body length was recorded. The whole body fatty acid profile and gene expression of fatty acid metabolism of larvae was detected. The DNA methylation status of fads2 gene was analyzed. Survival rate and body length of the experimental group was significantly increased, and the malformation rate was significantly decreased (P<0.05) at 15dph. The contents of linoleic acid (LA), arachidonic acid (ARA), linolenic acid (LNA), DHA, n-6PUFA and n-3PUFA increased significantly (P<0.05). The expression levels of pparα, acc1 and fas genes was significantly decreased, fads2 and fabp1 was significantly increased, and there was no significant difference in the expression level of elovlα (P>0.05). There was a CpG island from -750bp to -1050bp from the fads2 transcription start site, and the total length of the fragment was 301bp. There was 8 candidate CpG sites, of which 5 CpG sites was significantly demethylated (P<0.05). The fads2 promoter region was highly demethylation in terms of overall methylation levels(P<0.05). In this study, nutrition programming of larvae of Cynoglossus semilaevis with DHA can improve the survival ability of larvae, enhancing LC-HUFA synthesis by promoting fatty acid transport and desaturation in larvae to improving fatty acid metabolism. Early nutritional programming is involved in the demethylation of fads2 promoter which promoted the transcription of fads2 gene, this is one of the root causes of the increase in LC-HUFA. This study is helpful to develop high LC-HUFA quality larvae of Cynoglossus semilaevis, and provide a new idea for efficient breeding of Cynoglossus semilaevis. |
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