Increased intestinal permeability can be observed during the physiologic stress response and has been linked to suppression of animal health and performance. Previously published data have shown the efficacy of fluorescein isothiocyanate dextran (FITC-d; 4.17 mg/kg) as a marker of enteric inflammation and mucosal barrier function in multiple species. Fluorescein is a smaller, less expensive alternative molecule possessing similar properties. The following two experiments compared FITC-d and fluorescein as potential indicators of intestinal permeability in pre- and postweaned lambs administered daily intramuscular injections of dexamethasone (Dex; 0.1 mg/kg) for 1 wk. Experiment 1 consisted of five preweaned lambs that were placed in one of two treatment groups: fluorescein with Dex (F+Dex) or fluorescein only (F). On day 7, blood was collected before and 1 h after oral administration of fluorescein (50 mg/kg). Experiment 2 included 12 weaned lambs and four treatment groups: F+Dex, F, FITC-d with Dex (Fd+Dex), and FITC-d only (Fd). On day 7, blood was collected before and 2 h after oral administration of FITC-d (4.17 mg/kg) or fluorescein (50 mg/kg). Plasma fluorescence was reported as the ratio between T_1h/T₀ or T_2h/T₀ for experiment 1 or 2, respectively. Experiment 1 showed a significant increase in T_1h/T₀ ratio of F+Dex relative to F lambs (P = 0.05) indicative of increased leaky gut; however, no differences (P = 0.22) were obtained in experiment 2. Results of these experiments suggest fluorescein may serve as a suitable marker of enteric permeability in preruminant lambs, but not in those with functional rumens.

中文翻译：

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技术说明：荧光素作为反刍前羔羊肠粘膜屏障功能的指标。

在生理应激反应过程中可以观察到肠道通透性增加，并且与动物健康和生产性能的抑制有关。先前发表的数据已显示异硫氰酸葡聚糖荧光素（ FITC-d；4.17 mg/kg）作为多个物种肠道炎症和粘膜屏障功能标记物的功效。荧光素是一种更小、更便宜的替代分子，具有类似的特性。以下两个实验比较了 FITC-d 和荧光素作为断奶前和断奶后羔羊肠道通透性的潜在指标，每天肌内注射地塞米松（Dex；0.1 mg/kg），持续 1 周。实验 1 由五只断奶前的羔羊组成，它们被分为两个处理组之一：荧光素加 Dex ( F+Dex ) 或仅荧光素 ( F )。第7天，在口服荧光素（50mg/kg）之前和之后1小时采集血液。实验 2 包括 12 只断奶羔羊和四个处理组：F+Dex、F、FITC-d 加 Dex（Fd+Dex）和仅 FITC-d（Fd）。第7天，在口服FITC-d（4.17 mg/kg）或荧光素（50 mg/kg）之前和之后2小时采集血液。对于实验1或2，血浆荧光分别报告为T _1h / T ₀或T _2h / T ₀之间的比率。实验1显示F+Dex相对于F羔羊的T _1h / T ₀比率显着增加（ P = 0.05），表明肠漏增加；然而，实验 2 中没有获得差异（P = 0.22）。这些实验的结果表明，荧光素可以作为反刍前羔羊肠道通透性的合适标记，但不适用于具有功能性瘤胃的羔羊。