ABSTRACT: Zinc (Zn) is an important trace element in fish diets that is required for growth, immunity and antioxidant defense mechanisms. The current study assessed the effects of both organic and nanoparticle zinc oxide (ZnO and ZnO-NPs, respectively) on growth performance, immune response and the antimicrobial effect against Pseudomonas aeruginosa in African catfish Clarias gariepinus. Fish were fed either a control diet or diets supplemented with organic ZnO at concentrations of 20 and 30 mg kg^-1 or ZnO-NPs at concentrations of 20 and 30 mg kg^-1. After 60 d, a subset of the fish was injected intraperitoneally with 3 × 10⁷ CFU ml^-1 of P. aeruginosa. Results showed that body weight gain, feed conversion ratio and specific growth rates were significantly increased in ZnO-NPs20 compared to all other groups. The dietary supplementation with 20 mg kg^-1 of ZnO-NPs improved the antioxidant status of fish. Moreover, IgM, lysozyme and nitric oxide showed a significant increase in the fish which received the ZnO-NPs20-supplemented diet. A significant upregulation of growth and stress-related genes was seen in the ZnO-NPs20-supplemented group compared to other groups. However, there was no significant difference in the expression of immune-related genes among ZnO-NPs20, ZnO-NPs30 and ZnO30 groups. These findings highlight the potential use of nano-ZnO for improving growth performance, antioxidant status, immunological status and antibacterial activity against P. aeruginosa in African catfish.

中文翻译：

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纳米氧化锌膳食补充剂对非洲cat鱼Clarias gariepinus的生长性能，免疫调节和抗病性的功效

摘要：锌（Zn）是鱼饲料中重要的微量元素，是生长，免疫和抗氧化防御机制所必需的。目前的研究中评估有机和纳米颗粒氧化锌（ZnO和ZnO的纳米粒子，分别地）生长性能，免疫应答和针对抗微生物效果的效果假单胞菌aerugino š一个在非洲鲶鱼尖齿胡鲇。鱼饲喂对照饮食或在20和30的浓度添加有有机的ZnO饮食毫克千克^-1或在20和30毫克千克的浓度ZnO类的NP ^-1。60 d后，给部分鱼腹膜内注射3×10 ⁷ CFU ml ^-1的铜绿假单胞菌。结果表明，与所有其他组相比，ZnO-NPs20的体重增加，饲料转化率和比生长速率显着提高。膳食补充剂20 mg kg ^-1ZnO-NPs可以改善鱼类的抗氧化状态。此外，接受补充ZnO-NPs20饮食的鱼的IgM，溶菌酶和一氧化氮含量显着增加。与其他组相比，在补充ZnO-NPs20的组中观察到了生长和胁迫相关基因的显着上调。但是，在ZnO-NPs20，ZnO-NPs30和ZnO30组之间，免疫相关基因的表达没有显着差异。这些发现凸显了纳米氧化锌在改善非洲cat鱼铜绿假单胞菌的生长性能，抗氧化状态，免疫状态和抗菌活性方面的潜在用途。