This study evaluated the dietary effects of an ultrasound-assisted extract of Origanum vulgare on the growth, antioxidant and immune responses (serum and mucosal) and resistance of zebrafish (Danio rerio) against Aeromonas hydrophila. Four hundred and forty adult zebrafish were distributed into 12 tanks and fed 4 experimental diets including 0% (control), 0.5% (M1), 1% (M2) and 2% (M3) of the extract per kg⁻¹ diet for eight weeks. Fish were then challenged with A. hydrophila and mortality was recorded for 10 days. Results revealed that the extract exerted potent effects on growth parameters of weight gain and specific growth rate. The feed conversion ratio was significantly lower in fish fed extract-incorporated diets. O. vulgare extract improved antioxidant and immune responses, resulting in less sensitivity to oxidative stress and a higher survival rate when challenged with A. hydrophila. Overall, the greatest effects were observed in individuals with 1% dietary inclusion of the extract. These results suggest that the extract from the plant Origanum vulgare possesses a great potential to be used in the aquaculture industry and that zebrafish is an appropriate model for nutrition studies.

中文翻译：

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牛至 (Origanum vulgare) 提取物可增强斑马鱼 (Danio rerio) 的生长性能、血清和粘液先天免疫反应以及对嗜水气单胞菌挑战的抵抗力

本研究评估了超声辅助牛至提取物对斑马鱼 ( Danio rerio ) 生长、抗氧化和免疫反应（血清和粘膜）以及对嗜水气单胞菌抵抗力的饮食影响。将 440 条成年斑马鱼分配到 12 个水箱中，饲喂 4 种实验饲料，其中每千克−1 饲料中含有 0%（对照）、0.5%（M1）、1%（M2）和 2%（M3）提取物，共⁸只几周。然后用嗜水放线菌攻击鱼并记录10天的死亡率。结果表明，提取物对体重增加和特定生长率等生长参数产生有效影响。饲喂添加提取物的日粮的鱼的饲料转化率明显较低。O. vulgare提取物改善了抗氧化和免疫反应，从而降低了对氧化应激的敏感性，并在受到嗜水放线菌攻击时提高了存活率。总体而言，在饮食中添加 1% 提取物的个体中观察到了最大的效果。这些结果表明，牛至植物提取物在水产养殖业中具有巨大的应用潜力，并且斑马鱼是营养研究的合适模型。