The present study evaluated the effects of dietary onion (Allium cepa)powder and its extracts on growth, blood biochemical parameters, non‐specific immune parameters and potential disease resistance against pathogenic Aeromonas hydrophila infection in Oreochromis niloticus. Fish formulated diets containing onion powder (1% or 0.5%) or onion alcoholic extracts (1% or 0.5%). At the end of the experiment, the weight gain and specific growth rate were significantly increased than control. Besides, red blood cells (RBCs) and haemoglobin (Hb) showed a significant increase with insignificant changes of leukocytic cells count (WBCs), triglycerides, creatinine and uric acid levels. Results showed significant increase of total protein and albumin, and significant enhancement of innate immune response including serum globulins, serum antiprotease, lysozyme activities, myeloperoxidase content and the phagocytic index compared with the control group. Meanwhile feeding on onion increased superoxide dismutase, catalase activities and glutathione‐S‐transferase but significantly decreased hepatic peroxidase. The cumulative mortality of O. niloticus injected with A. hydrophila exhibited relatively low mortality levels in all onion supplemented groups. The relative per cent survivals were 100%, 100%, 80% and 70% in 1% onion powder, 0.5% powder, 1% extract and 0.5% extract groups, respectively, compared with control (60%). Additionally, there was a significant increase in relative immune gene expressions of interleukin 1‐beta (IL‐1β), and transforming growth factor‐beta 1 (TGF‐β1) in head kidney tissues of treated groups than the control. These results confirm the anti‐inflammatory and antioxidative activities of dietary onion with its beneficial effects on growth performance and disease resistance against A. hydrophila in O. niloticus.

中文翻译：

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洋葱对尼罗罗非鱼日粮的影响：生长改善，抗氧化剂，抗炎和抗病性的观点

本研究评估了膳食洋葱粉（Allium cepa）及其提取物对尼罗罗非鱼（Oreochromis niloticus）致病性嗜水气单胞菌感染的生长，血液生化参数，非特异性免疫参数和潜在疾病抗性的影响。鱼类配方饮食，其中包含洋葱粉（1％或0.5％）或洋葱酒精提取物（1％或0.5％）。在实验结束时，体重增加和比生长速率显着高于对照。此外，红细胞（RBC）和血红蛋白（Hb）显着增加，而白细胞计数（WBCs），甘油三酸酯，肌酐和尿酸水平无明显变化。结果显示，与对照组相比，总蛋白和白蛋白显着增加，并且先天免疫应答（包括血清球蛋白，血清抗蛋白酶，溶菌酶活性，髓过氧化物酶含量和吞噬指数）显着提高。同时，以洋葱为食增加了超氧化物歧化酶，过氧化氢酶活性和谷胱甘肽-S-转移酶，但大大降低了肝过氧化物酶。在所有洋葱补充组中，注射亲水性链球菌的尼罗罗非鱼均显示出较低的死亡率。与对照组（60％）相比，在1％洋葱粉，0.5％粉末，1％提取物和0.5％提取物组中，相对存活率分别为100％，100％，80％和70％。此外，与对照组相比，治疗组头部肾脏组织中白介素1-β（IL-1β）和转化生长因子-β1（TGF-β1）的相对免疫基因表达显着增加。这些结果证实了饮食洋葱的抗炎和抗氧化活性生长性能和抗耐病的有利影响嗜水气单在尼罗罗非鱼。