Centro Interdisciplinar de Investigação Marinha e Ambiental, Matosinhos, Portugal.
Centro Interdisciplinar de Investigação Marinha e Ambiental, Matosinhos, Portugal; Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal; Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
Fish Shellfish Immunol. 2020 Nov;106:451-463. doi: 10.1016/j.fsi.2020.07.060. Epub 2020 Aug 13.
The present study was designed to determine the modulatory effects of arginine and citrulline dietary supplementation on the immune condition and inflammatory response of European seabass, Dicentrarchus labrax. Four diets were manufactured: a control diet (CTRL) was formulated to meet the indispensable amino acids profile established for seabass. Based on this formulation, three other diets were supplemented with l-arginine at two different levels (0.5% and 1%, ARG1 and ARG2, respectively) and l-citrulline at 0.5% (CIT). Fish were fed these diets for 2 or 4 weeks under controlled conditions. At the end of 4 weeks, fish from all dietary treatments were intraperitoneally-injected with Photobacterium damselae piscicida and sampled after 4, 24 our 48 h. Immune status was characterized by a lymphocyte time-dependent decrease regardless of dietary treatment, whereas peroxidase values dropped in time in fish fed ARG1 and ARG2 and was lower at 4 weeks in fish fed ARG1 than in fish fed CTRL. Up-regulation of several genes was more evident in ARG1-and CIT-fed fish, though pro-inflammatory cytokines were down-regulated by CIT dietary treatment. Following immune stimulation, seabass fed ARG1 showed a decrease in neutrophils and monocytes circulating numbers. On the other hand, expression of 17 selected immune and inflammatory responses genes was barely affected by dietary treatments. Based on the analyzed parameters, results suggest an active role of dietary arginine/citrulline supplementation in modulating immune defences that seem to translate into a suppressed immune repertoire, mostly at the cell response level. The observed changes due to citrulline dietary supplementation were in part similar to those caused by arginine, suggesting that citrulline might have been used by macrophages as an arginine precursor and then engaged in similar immune-impairment leading mechanisms.
本研究旨在确定精氨酸和瓜氨酸饮食补充对欧洲鲈鱼（Dicentrarchus labrax）免疫状况和炎症反应的调节作用。设计了四种饮食：对照饮食（CTRL）根据鲈鱼必需氨基酸模式配制，以满足鲈鱼的需求。在此配方基础上，另外三种饮食分别补充 0.5%和 1%的 l-精氨酸（ARG1 和 ARG2）和 0.5%的 l-瓜氨酸（CIT）。在受控条件下，鱼分别用这些饮食喂养 2 或 4 周。4 周结束时，所有饮食处理的鱼均经腹腔注射杀鱼假单胞菌（Photobacterium damselae piscicida），并在 4、24 或 48 小时后取样。免疫状况的特征是淋巴细胞随时间的依赖性减少，无论饮食处理如何，而过氧化物酶值随时间的推移在 ARG1 和 ARG2 喂养的鱼中下降，在 ARG1 喂养的鱼中 4 周时比在 CTRL 喂养的鱼中更低。ARG1 和 CIT 喂养的鱼中几种基因的上调更为明显，尽管 CIT 饮食处理下调了促炎细胞因子。在免疫刺激后，ARG1 喂养的鲈鱼中循环中性粒细胞和单核细胞数量减少。另一方面，17 个选定的免疫和炎症反应基因的表达几乎不受饮食处理的影响。基于分析的参数，结果表明饮食精氨酸/瓜氨酸补充在调节免疫防御方面发挥积极作用，这似乎转化为免疫反应谱的抑制，主要在细胞反应水平上。由于饮食补充瓜氨酸引起的变化在某种程度上与精氨酸引起的变化相似，这表明瓜氨酸可能被巨噬细胞用作精氨酸前体，然后参与类似的免疫抑制作用机制。
