The French Associates Institute for Agriculture and Biotechnology for Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Beersheba, Israel.
The Skin Research Institute, Dead Sea and Arava Science Center, Masada, Israel.
Front Immunol. 2018 Sep 6;9:1960. doi: 10.3389/fimmu.2018.01960. eCollection 2018.
Arachidonic acid (ARA, 20:4-6) and dihomo-γ-linolenic acid (DGLA, 20:3-6) are omega-6 long-chain polyunsaturated fatty acids (LC-PUFA), which are key precursors for lipid mediators of the immune system and inflammatory response. The microalga (WT) and its Δ5-desaturase mutant P127 (MUT) are unique photosynthetic sources for ARA and DGLA, respectively. This study explores the effect of dietary supplementation with and P127 biomass on tissue fatty acid composition, immune function, and disease resistance in zebrafish (). The broken microalgal biomass was added to commercial fish feed at 7.5 and 15% (w/w), providing 21.8 mg/g feed ARA for the WT-supplemented group and 13.6 mg/g feed DGLA for the MUT-supplemented group at the 15% inclusion levels. An unsupplemented group was used as the control. After 1 month of feeding, fish were challenged with . Fish were sampled before the challenge and 1 week after the challenge for various analyses. Tissue ARA and DGLA levels significantly increased in the liver, corresponding to microalgal supplementation levels. The elevated expression of specific immune-related genes was evident in the kidneys in all treatment groups after 1 month of feeding, including genes related to eicosanoid synthesis, lysozyme, and NF-κB. In the liver, microalgal supplementation led to the upregulation of genes related to immune function and antioxidant defense while the expression of examined genes involved in ARA metabolism was downregulated. Importantly, fish fed with 15% of both WT- and MUT-supplemented feed showed significantly ( < 0.05) higher survival percentages (78 and 68%, respectively, as compared to only 46% in the control group). The elevated expression of genes related to inflammatory and immune responses was evident post-challenge. Collectively, the results of the current study demonstrate the potential of microalgae-derived dietary ARA and DGLA in improving immune competence and resistance to bacterial infection in zebrafish as a model organism.
花生四烯酸（ARA，20:4-6）和二高-γ-亚麻酸（DGLA，20:3-6）是ω-6 长链多不饱和脂肪酸（LC-PUFA），是免疫系统和炎症反应的脂质介质的关键前体。微藻（WT）及其Δ5-去饱和酶突变体 P127（MUT）分别是 ARA 和 DGLA 的独特光合来源。本研究探讨了用 WT 和 P127 生物质饲料补充对斑马鱼（）组织脂肪酸组成、免疫功能和抗病性的影响。将破碎的微藻生物质以 7.5%和 15%（w/w）的比例添加到商业鱼饲料中，在 15%的添加水平下，WT 补充组的饲料中 ARA 含量为 21.8mg/g，MUT 补充组的饲料中 DGLA 含量为 13.6mg/g。未补充组作为对照组。喂食 1 个月后，用进行攻毒。在攻毒前和攻毒后 1 周取样进行各种分析。肝组织中 ARA 和 DGLA 水平随微藻补充水平显著升高。在所有处理组中，喂食 1 个月后，肾脏中特定的免疫相关基因表达明显升高，包括与类花生酸合成、溶菌酶和 NF-κB 相关的基因。在肝脏中，微藻补充导致与免疫功能和抗氧化防御相关的基因上调，而参与 ARA 代谢的检查基因表达下调。重要的是，喂食 15%的 WT 和 MUT 补充饲料的鱼的存活率显著（<0.05）更高（分别为 78%和 68%，而对照组仅为 46%）。攻毒后炎症和免疫反应相关基因的表达明显升高。总的来说，本研究结果表明，作为模式生物的斑马鱼从微藻中获得的膳食 ARA 和 DGLA 具有提高免疫能力和抵抗细菌感染的潜力。
