The present study was performed to explore the immunotoxicological effects of the lambda cyhalothrin (LCH) insecticide and evaluate the efficiency of Thyme powder (TP) as a fish supplement in attenuation of LCH impact on Oreochromis niloticus (O. niloticus) fish. Fish was sampled following 30-days exposure to LCH (1/6 LC50: 0.48 μg/L) and TP (2%) supplementation, individually or in combination. The growth performance, immune status, biochemical indices, and mRNA expression pattern changes of stress and immune-encoding genes in the liver and spleen tissues, respectively, through real-time polymerase chain reaction (RT-PCR) analysis, were evaluated. The findings showed that LCH exposure caused a significant lowering in most of the estimated variables including growth performance, hematological and immunological indices. Moreover, LCH disrupted the oxidant/antioxidant status and dysregulated the expression of stress and immune-related genes, downregulating the mRNA transcript level of Immunoglobulin M heavy chain (IgM), Interferon (IFN-γ), CXC-chemokine, and Toll-like receptors (TLR-7) in the spleen. However, mRNA expression of Myxovirus resistance (Mx) gene remained unaffected. In liver tissue, the heat shock protein (HSP-70) expression was upregulated, while that of cytochrome P450 1A (CYP 1A) was downregulated. TP (2%) supplementation elicited a significant modulation in aforementioned indices; however, their levels did not attain that of the control values. Our findings concluded that LCH affects the O. niloticus immune response through the negative transcriptional influence on genes linked to immunity and induction of oxidative injury of the immune organs. Besides, dietary TP (2%) could be a proper candidate to modulate the compromised immunity in response to LCH exposure in O. niloticus aquaculture.

中文翻译：

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尼罗罗非鱼鱼暴露于氟氯氰菊酯并同时饲喂百里香粉（百里香L.）的双重免疫和氧化反应：应激和免疫编码基因表达。

进行本研究以探讨λ氟氯氰菊酯（LCH）杀虫剂的免疫毒理作用，并评估百里香粉（TP）作为鱼类补品的效果，以减轻LCH对尼罗罗非鱼（O.chroma niloticus）鱼的影响。在单独或组合使用LCH（1/6 LC50：0.48μg/ L）和TP（2％）补充30天后，对鱼进行采样。通过实时聚合酶链反应（RT-PCR）分析，分别评估了肝脏和脾脏组织中应激和免疫编码基因的生长性能，免疫状态，生化指标和mRNA表达模式的变化。研究结果表明，LCH暴露导致大多数估计变量（包括生长性能，血液学和免疫学指标）显着降低。此外，LCH破坏了氧化剂/抗氧化剂的状态并异常调节了压力和免疫相关基因的表达，下调了免疫球蛋白M重链（IgM），干扰素（IFN-γ），CXC趋化因子和Toll样受体的mRNA转录水平（ TLR-7）在脾脏中。但是，粘液病毒抗性（Mx）基因的mRNA表达仍不受影响。在肝组织中，热休克蛋白（HSP-70）的表达上调，而细胞色素P450 1A（CYP 1A）的表达下调。TP（2％）补充引起上述指标的显着调节；但是，它们的水平没有达到对照值。我们的发现得出结论，LCH通过对与免疫相关的基因和免疫器官氧化损伤的诱导产生负转录影响，从而影响了罗非鱼的免疫反应。除了，