College of Animal Science & Technology, Gansu Agricultural University, Lanzhou, 730070, PR China.
College of Animal Science & Technology, Gansu Agricultural University, Lanzhou, 730070, PR China.
Fish Shellfish Immunol. 2023 Feb;133:108537. doi: 10.1016/j.fsi.2023.108537. Epub 2023 Jan 11.
Heat stress-induced intestinal damage is a key event in fish pathology. Nano-selenium (nano-Se) shows remarkably high biological activity and low toxicity, making it an ideal and ecological Se formulation; however, to date, the protective effects of nano-Se against heat stress-induced intestinal injury and pertinent molecular mechanisms remain unknown. Herein, rainbow trout (Oncorhynchus mykiss) were fed either a basal diet or basal diet + 5 mg/kg nano-Se. Samples were collected before (18 °C for 9 days; CG18 and Se18 groups) and after (24 °C for 8 h; CG24 and Se24 groups) heat stress treatment. On heat stress exposure, intestinal villus height, muscularis thickness, and goblet cell number decreased, and expression of tight junction proteins (ZO-1, occludin, and claudin-8d) was downregulated; dietary supplementation with nano-Se alleviated these effects. Furthermore, in the presence of nano-Se, catalase activity was elevated, and expression of diverse heat shock proteins (Hsp70b, Hsp90α, and Hsp30), selenoproteins (Gpx1a, Gpx1b1, and Trx), and anti-inflammatory cytokine (TGF-β) was upregulated. In contrast, nano-Se supplementation significantly alleviated the increase of the expression of pro-inflammatory cytokines (IL-1β and TNF-α) and the malondialdehyde content. We also observed that heat stress markedly increased the relative abundance of Actinobacteria, Firmicutes, Methylobacterium, Akkermansia, and Deinococcus and decreased that of Proteobacteria; nano-Se supplementation restored these changes, making their distribution similar to that in the control group. Overall, our findings suggest that nano-Se plays a protective role against heat stress-induced intestinal damage in rainbow trout by promoting the recovery of antioxidant enzyme activity, enhancing protein repair, alleviating inflammatory responses, and restoring intestinal microbiota composition.
热应激诱导的肠道损伤是鱼类病理学中的一个关键事件。纳米硒（nano-Se）表现出极高的生物活性和低毒性，是一种理想的、生态友好型的硒制剂；然而，迄今为止，纳米硒对热应激诱导的肠道损伤的保护作用及其相关分子机制尚不清楚。在此，我们用基础饲料或基础饲料+5mg/kg 纳米硒喂养虹鳟（Oncorhynchus mykiss）。在热应激处理前后（18°C 下 9 天；CG18 和 Se18 组；24°C 下 8 小时；CG24 和 Se24 组）收集样本。在暴露于热应激时，肠道绒毛高度、肌层厚度和杯状细胞数量减少，紧密连接蛋白（ZO-1、occludin 和 claudin-8d）的表达下调；膳食补充纳米硒缓解了这些作用。此外，在纳米硒存在的情况下，过氧化氢酶活性升高，多种热休克蛋白（Hsp70b、Hsp90α 和 Hsp30）、硒蛋白（Gpx1a、Gpx1b1 和 Trx）和抗炎细胞因子（TGF-β）的表达上调。相反，纳米硒补充剂显著减轻了促炎细胞因子（IL-1β 和 TNF-α）的表达增加和丙二醛含量的增加。我们还观察到，热应激显著增加了放线菌门、厚壁菌门、Methylobacterium、Akkermansia 和 Deinococcus 的相对丰度，降低了变形菌门的相对丰度；纳米硒补充剂恢复了这些变化，使其分布与对照组相似。总的来说，我们的研究结果表明，纳米硒通过促进抗氧化酶活性的恢复、增强蛋白质修复、减轻炎症反应和恢复肠道微生物群落组成，在虹鳟中发挥保护作用，防止热应激引起的肠道损伤。
