Animal Wealth Development Department, Faculty of Veterinary Medicine, Zagazig University, Egypt.
Fish Disease and Management Department, Faculty of Veterinary Medicine, Zagazig University, Egypt.
Fish Shellfish Immunol. 2019 Oct;93:336-343. doi: 10.1016/j.fsi.2019.07.067. Epub 2019 Jul 25.
The present investigation was performed to evaluate the efficiency of Zinc oxide (ZnO) as a fish feed additive in immunomodulation of Oreochromis niloticus. Fish were fed on ZnO nano-particles (nZnO) and conventional (ZnO) in two concentrations (30 and 60 mg/kg diet), in addition to the control fish which was fed on Zn free diet. After 6° days, the highest survival rate was recorded in the nZnO -supplemented group. The total antioxidant capacity (TAC) and antioxidant enzymes were improved in different dietary Zn supplementation, obviously in the nZnO -supplemented group, while the lowest antioxidant status was noticed nZnO supplemented fish. The lipid peroxides (MDA) level was diminished upon Zn supplementation, particularly in nZnO-supplemented group but showed a significant elevation in the nZnO-supplemented group. Furthermore, the immune parameters examined, lysozyme activity, bactericidal activity, and IgM were significantly higher in ZnO, and nZnO supplemented groups. The C-reactive protein (CRP) level showed no significant increase in response to Zn supplementation in the both forms at level of 30 mg/kg diet, but showed marked elevation in nZnO- supplemented group. The mRNA expression profile of both interleukin 8 (IL-8), interleukin 1, beta (IL-1β) encoding genes showed an up-regulation that was found in all Zn- supplemented groups, but more pronounced in nZnO-supplemented group. On the other hand, the expression pattern of myxovirus resistance (Mx)-encoding gene showed no remarkable difference between the Zn- supplemented and control fish. The expression level of CXC-chemokine, toll-like receptor 7 (TLR-7), immunoglobulin M heavy chain (IgM heavy chain) and interferon gamma (IFN-γ) gene was upregulated in Zn-supplemented groups particularly in the nZnO- supplemented group. While, the lowest expression was found in nZnO- and ZnO-supplemented groups. Here, Zn supplementation promoted the immune and antioxidant strength in fish mainly in nano form at the level of 30 mg/kg diet but not at 60 mg/kg diet that disrupt the immune and antioxidant status and promote inflammatory response.
本研究旨在评估氧化锌（ZnO）作为鱼类饲料添加剂在奥利亚罗非鱼（Oreochromis niloticus）免疫调节中的功效。实验中，将鱼分为三组，分别投喂含纳米氧化锌（nZnO）和常规氧化锌（ZnO）的饲料，浓度分别为 30 和 60mg/kg 饲料，另外一组投喂不含 Zn 的饲料作为对照。6 天后，nZnO 组的存活率最高。不同饲料 Zn 补充组的总抗氧化能力（TAC）和抗氧化酶均有所提高，其中 nZnO 组最为明显，而 nZnO 组的抗氧化状态最低。脂质过氧化物（MDA）水平随 Zn 补充而降低，尤其是 nZnO 组，但 nZnO 组 MDA 水平显著升高。此外，ZnO 和 nZnO 补充组的溶菌酶活性、杀菌活性和 IgM 等免疫参数显著升高。在 30mg/kg 饲料水平下，两种形式的 Zn 补充均未引起 CRP 水平显著升高，但 nZnO 组的 CRP 水平显著升高。白细胞介素 8（IL-8）和白细胞介素 1β（IL-1β）编码基因的 mRNA 表达谱均上调，Zn 补充组均有发现，但 nZnO 组更为明显。另一方面，Mx 编码基因的表达模式在 Zn 补充组和对照组之间没有显著差异。在 Zn 补充组，CXCL-chemokine、Toll-like receptor 7（TLR-7）、免疫球蛋白 M 重链（IgM heavy chain）和干扰素γ（IFN-γ）基因的表达水平上调，尤其是 nZnO 组。而 nZnO 和 ZnO 组的表达水平最低。综上所述，Zn 补充在 30mg/kg 饲料水平下可增强鱼类的免疫和抗氧化能力，主要以纳米形式存在，但在 60mg/kg 饲料水平下会破坏免疫和抗氧化状态，并促进炎症反应。
