A synbiotic improves the immunity of white shrimp, Litopenaeus vannamei: Metabolomic analysis reveal compelling evidence
A synbiotic improves the immunity of white shrimp, Litopenaeus vannamei: Metabolomic analysis reveal compelling evidence
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DOI：
10.1016/j.fsi.2018.05.031
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发表时间：
2018-08-01
影响因子：
4.7
通讯作者：
Liu, Chun-Hung
中科院分区：
文献类型：
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作者：
Truong-Giang Huynh;Cheng, Ann-Chang;Liu, Chun-Hung
在本研究中，我们检测了一种由低聚半乳糖（GOS）和益生菌植物乳杆菌7 - 40组成的经饲料投喂的合生元对凡纳滨对虾免疫反应、免疫相关基因表达以及对溶藻弧菌抗病性的协同效应。为了揭示合生元在激活对虾免疫系统中的调节作用，采用基于氢 - 1核磁共振（NMR）的代谢组学分析来研究肝胰腺代谢物，然后通过反相高效液相色谱（RP - HPLC）和分光光度法分析在肝胰腺和血浆中确认显著改变的代谢物。对虾投喂四种实验饲料60天，包括不含GOS或益生菌的基础饲料（对照）、0.4% GOS（益生元组，PRE）、益生菌（益生菌组，PRO）以及0.4% GOS与益生菌组合（合生元组，SYN）。结果表明，合生元饲料显著提高了凡纳滨对虾在溶藻弧菌注射24小时后的存活率。与其他处理组和对照组相比，投喂合生元饲料的对虾的免疫参数，如酚氧化酶活性、呼吸爆发、吞噬活性以及基因表达，包括酚氧化酶原I、丝氨酸蛋白酶和过氧化物酶，均显著提高。此外，氢 - 1 - NMR分析结果显示，合生元组和对照组之间有22种肝胰腺代谢物匹配并被鉴定出来，其中三种代谢物，即肌苷酸（IMP）、缬氨酸和甜菜碱，在合生元组中显著增加。使用RP - HPLC和分光光度法进行确认表明，IMP在肝胰腺中含量较高，但在对虾血浆中含量不高；相反，缬氨酸和甜菜碱代谢物在肝胰腺和血浆中浓度均较高。我们的研究结果表明，GOS和益生菌通过诱导肝胰腺中一种核苷酸（IMP）、一种支链氨基酸（缬氨酸）和一种甲基供体（甜菜碱）的合成，对增强凡纳滨对虾对溶藻弧菌感染的免疫力和抗病性具有协同作用，这些物质随后释放到血浆中并被血细胞直接摄取，从而引发细胞中的黑化和吞噬过程。
In this study, we examined the synergistic effects of a diet-administered synbiotic comprising galactooligosaccharide (GOS) and the probiotic Lactobacillus plantar 7-40 on immune responses, immune-related gene expressions, and disease resistance to Vibrio alginolyticus in white shrimp Litopenaeus vannamei. To unravel the regulatory role of the synbiotic in activating the immune system of shrimp, H-1 nuclear magnetic resonance (NMR)-based metabolomic analysis were used to investigate hepatopancreas metabolites, then significantly altered metabolites were confirmed in both the hepatopancreas and plasma by reverse-phase high-performance liquid chromatography (RP-HPLC) and spectrophotometric analysis. Shrimp were fed four experimental diets for 60 days, including a basal diet with no GOS or probiotic (control), 0.4% GOS (PRE), probiotic (PRO), and 0.4% GOS in combination with the probiotic (SYN). Results showed that the SYN diet significantly increased survival of L. vannamei 24 h after a V. alginolyticus injection. Immune parameters such as phenoloxidase activity, respiratory bursts, phagocytic activity and gene expressions, including prophenoloxidase I, serine proteinase, and peroxinectin, of shrimp fed the SYN diet significantly increased, compared to the other treatments and control. In addition, results from the H-1-NMR analysis revealed that 22 hepatopancreas metabolites were matched and identified between the SYN and control groups, among which three metabolites, i.e., inosine monophosphate (IMP), valine, and betaine, significantly increased in the SYN group. Confirmation using RP-HPLC and spectrophotometric methods showed that IMP presented high amounts in the hepatopancreas, but not in the plasma of shrimp; in contrast, valine and betaine metabolites were in high concentrations in both the hepatopancreas and plasma. Our results suggested that GOS and the probiotic had a synergistic effect on enhancing immunity and disease resistance of L. vannamei against V. alginolyticus infection through inducing syntheses of a nucleotide (IMP), a branched amino acid (valine), and a methyl group donor (betaine) in the hepatopancreas, which were then released into the plasma and directly taken up by hemocytes, resulting in a triggering of melanization and phagocytosis processes in cells.