In recent years, supplementing herbal medicines to fish diets in the aquaculture industry as a growth stimulant and immunostimulant is a common practice. In the present study, we investigated the effect of hydroalcoholic extract of dill on the growth performance and body composition of Rainbow Trout Oncorhynchus mykiss and its inhibitory effect against Aeromonas hydrophila in vitro. We also evaluated the immune responses and antioxidant system in fish that were fed dill diets over a period of 56 d. For this purpose, 180 Rainbow Trout fingerlings (initial weight 13.30 ± 0.22 g; mean ± SD) were purchased and they were fed four experimental treatments, which included a control diet and diets that were supplemented with 1Dill (1 g/kg dill extract), 1.5Dill (1.5 g/kg dill extract), or 3Dill (3 g/kg dill extract). According to the results, the fish that were fed 1Dill (54.70 g) and 1.5Dill (53.19 g) diets had significantly higher weight gain, although the feed conversion ratio was not significantly different among groups. However, the fish that were fed the 1.5Dill (62.55%) diet had significantly higher protein contents in the body than those that were fed the 3Dill (60.09%) treatment; the fish that were fed the 3Dill (29.00%) diet had higher lipid content than those that were fed the other diets. Regarding immune and antioxidant systems, the Rainbow Trout that were fed the 1.5Dill diet had significantly higher values of lysozyme in their serum (53.33 U/mL ), alternative complement pathway hemolytic activity (146.33 U/mL ), superoxide dismutase (52.33 U/mg protein), and catalase activity (164.66 U/mg protein) than the others did. Dill extracts in different dosages had no inhibitory effect against A. hydrophila in vitro. In summary, it can be concluded that the 1.5Dill diet can be used as a natural stimulant of growth, immunity, and the antioxidant system in the aquaculture industry.

中文翻译：

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莳萝提取物对虹鳟鱼生长性能、身体成分、免疫系统和抗氧化系统的影响

近年来，在水产养殖业的鱼类饲料中补充草药作为生长刺激剂和免疫刺激剂是一种普遍做法。在本研究中，我们研究了莳萝的水醇提取物对虹鳟鱼 Oncorhynchus mykiss 生长性能和身体成分的影响及其对嗜水气单胞菌的体外抑制作用。我们还评估了在 56 天内喂食莳萝饲料的鱼的免疫反应和抗氧化系统。为此，购买了 180 条虹鳟鱼鱼种（初始重量 13.30 ± 0.22 g；平均值 ± SD），并饲喂四种实验处理，包括对照日粮和补充 1Dill（1 g/kg 莳萝提取物）的日粮、1.5Dill（1.5 g/kg 莳萝提取物）或 3Dill（3 g/kg 莳萝提取物）。根据结果​​，喂食 1 莳萝（54.70 克）和 1.5 莳萝（53.19 克）日粮的鱼体重增加显着更高，尽管饲料转化率在各组之间没有显着差异。然而，喂食 1.5Dill (62.55%) 饮食的鱼体内蛋白质含量明显高于喂食 3Dill (60.09%) 治疗的鱼；喂食 3Dill (29.00%) 饮食的鱼的脂质含量高于喂食其他饮食的鱼。关于免疫和抗氧化系统，喂食 1.5 莳萝饮食的虹鳟鱼血清中的溶菌酶 (53.33 U/mL)、替代补体途径溶血活性 (146.33 U/mL)、超氧化物歧化酶 (52.33 U/mL) 值显着升高mg 蛋白质）和过氧化氢酶活性（164.66 U/mg 蛋白质）。不同剂量的莳萝提取物在体外对嗜水曲霉没有抑制作用。综上所述，可以得出结论，1.5莳萝日粮在水产养殖业中可用作生长、免疫和抗氧化系统的天然刺激剂。