Department of Aquatic Animal Medicine, Faculty of Veterinary Medicine, Zagazig University, PO Box 44511, Zagazig, Sharkia, Egypt.
Department of Fish Diseases and Management, Faculty of Veterinary Medicine, Suez Canal University, PO Box 41522, Ismailia, Egypt.
Fish Shellfish Immunol. 2023 Jul;138:108842. doi: 10.1016/j.fsi.2023.108842. Epub 2023 May 18.
Aeromonas veronii is a pathogenic bacterium associated with various diseases in aquaculture. However, few studies address the antibacterial activity using nanoparticles (NPs). Hence, the current study is innovative to evaluate the antibacterial efficacy of silica nanoparticles (SiNPs) against A. veronii infection in-vitro with a trial for treatment in-vivo. Primarily, we assessed the in-vitro antibacterial activity against A. veronii. Further, we investigated the hematological profile, immune-antioxidant response, and gene expression of African catfish (Clarias gariepinus) in response to SiNPs exposure and the A. veronii challenge. Fish (N = 120; weight: 90 ± 6.19 g) were distributed into four groups (30 fish/group) for a ten-days-treatment trial. The first (control) and second (SiNPs) groups were treated with 0 mg/L and 20 mg/L SiNPs in water, respectively. The third (A. veronii) and fourth (SiNPs + A. veronii) groups were treated with 0 mg/L and 20 mg/L SiNPs in water, respectively, and infected with A. veronii (1.5 × 10 CFU/mL). Results demonstrated that SiNPs displayed an in-vitro antibacterial activity against A. veronii with a 21 mm inhibitory zone. A. veronii infection caused a high mortality rate (56.67%) and substantial reductions in hematological indices and immune indicators [nitric oxide (NO) and immunoglobulin M (IgM)]. Additionally, marked decline in the level of antioxidants [superoxide dismutase (SOD), catalase (CAT), and reduced glutathione content (GSH)] as well as down-regulation in the immune-related genes [interleukins (IL-1β and IL-8) and tumor necrosis factor-alpha (TNF-α)] and antioxidant-related genes [SOD1, glutathione peroxidase (GPx), and glutathione-S-transferase (GST)] were the consequences of A. veronii infection. Surprisingly, treatment of A. veronii-infected fish with SiNPs lessened the mortality rate, enhanced the blood picture, modulated the immune-antioxidant parameters, and resulted in gene up-regulation. Overall, this study encompasses the significant role of SiNPs, a new versatile tool for combating hematological, immuno-antioxidant alterations, and gene down-regulation induced by A. veronii infection and sustainable aquaculture production.
维氏气单胞菌是一种与水产养殖中各种疾病相关的致病性细菌。然而，很少有研究使用纳米颗粒（NPs）来评估其抗菌活性。因此，本研究创新性地评估了硅纳米颗粒（SiNPs）在体外对抗维氏气单胞菌感染的抗菌功效，并进行了体内治疗试验。首先，我们评估了 SiNPs 对维氏气单胞菌的体外抗菌活性。此外，我们研究了非洲鲶鱼（Clarias gariepinus）在暴露于 SiNPs 和维氏气单胞菌挑战后的血液学特征、免疫抗氧化反应和基因表达。将 120 条鱼（N = 120；体重：90 ± 6.19 g）分为 4 组（每组 30 条）进行为期 10 天的治疗试验。第一组（对照组）和第二组（SiNPs 组）分别用 0 mg/L 和 20 mg/L 的 SiNPs 在水中处理。第三组（维氏气单胞菌组）和第四组（SiNPs + 维氏气单胞菌组）分别用 0 mg/L 和 20 mg/L 的 SiNPs 在水中处理，并感染维氏气单胞菌（1.5 × 10 CFU/mL）。结果表明，SiNPs 对维氏气单胞菌表现出体外抗菌活性，抑菌圈为 21mm。维氏气单胞菌感染导致高死亡率（56.67%）和血液学指标及免疫指标[一氧化氮（NO）和免疫球蛋白 M（IgM）]的显著降低。此外，抗氧化剂[超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和还原型谷胱甘肽含量（GSH）]水平显著下降，以及免疫相关基因[白细胞介素（IL-1β和 IL-8）和肿瘤坏死因子-α（TNF-α）]和抗氧化相关基因[SOD1、谷胱甘肽过氧化物酶（GPx）和谷胱甘肽-S-转移酶（GST）]的下调是维氏气单胞菌感染的后果。令人惊讶的是，用 SiNPs 治疗感染维氏气单胞菌的鱼可降低死亡率，增强血液状况，调节免疫抗氧化参数，并导致基因上调。总的来说，本研究涵盖了 SiNPs 的重要作用，SiNPs 是一种新的多功能工具，可用于对抗由维氏气单胞菌感染引起的血液学、免疫抗氧化变化和基因下调，并实现可持续水产养殖生产。
