Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China.
Zhejiang Institute of Freshwater Fishery, Huzhou, 313001, PR China.
Fish Shellfish Immunol. 2022 Jan;120:458-469. doi: 10.1016/j.fsi.2021.12.025. Epub 2021 Dec 18.
This study aimed to investigate the effects of dietary tea tree oil (TTO) on the performance, intestinal antioxidant capacity, and non-specific immunity after ammonia nitrogen stress in Macrobrachium rosenbergii. Six experimental diets were formulated with 0, 25, 50, 100, 200, 400 mg/kg TTO, respectively. A total of 900 prawns (average initial weight, 0.39 ± 0.01 g) were randomly assigned to 6 groups in triplicate in 18 tanks. After an 8-week feeding trial, 20 prawns from each tank were changed with 20 mg/L ammonia stress for 24 h. The results showed that 100 mg/kg TTO significantly increased prawns performance and survival rate compared with the control group. Moreover, 100 and 200 mg/kg TTO significantly improved intestinal antioxidant capabilities by increasing SOD enzyme activities and decreasing MDA levels. In addition, the prawns fed with 100 mg/kg TTO diet showed the highest survival rate under ammonia stress. After ammonia stress, the group of 100 mg/kg TTO significantly improved antioxidant capacity by increasing hemolymph respiratory burst activity, as well as intestinal anti-superoxide anion activity and SOD. Coincidentally, 100 mg/kg TTO significantly upregulated the intestinal relative expression of antioxidant-related genes (peroxiredoxin-5). Further, it was found that 100 mg/kg TTO activated the toll-dorsal pathway in prawns, which performed the similar function as the classic NF-κB pathway by upregulating the TNF-α and IL-1. Finally, 100 mg/kg TTO increased the levels of iNOS activities and NO contents after ammonia stress and enhanced non-specific immunity. The results indicated that 100 mg/kg TTO could significantly improve the M. rosenbergii performance, antioxidant capacity and ammonia stress resistance. We suggested that the mechanisms may be attributed to that TTO enhanced the antioxidant capacity and non-specific immunity of M. rosenbergii via the NF-κB signal pathway.
本研究旨在探讨日粮茶树油（TTO）对罗氏沼虾在氨氮胁迫后性能、肠道抗氧化能力和非特异性免疫的影响。共配制了 6 种实验饲料，分别添加 0、25、50、100、200、400mg/kg TTO。将 900 只虾（平均初始体重 0.39±0.01g）随机分为 6 组，每组 3 个重复，共 18 个水槽。经过 8 周的饲养试验后，将每个水槽的 20 只虾换成 20mg/L 的氨氮胁迫 24h。结果表明，与对照组相比，100mg/kg TTO 显著提高了虾的性能和存活率。此外，100 和 200mg/kg TTO 通过提高 SOD 酶活性和降低 MDA 水平显著改善了肠道抗氧化能力。此外，在氨氮胁迫下，100mg/kg TTO 组虾的存活率最高。在氨氮胁迫后，100mg/kg TTO 组通过增加血淋巴呼吸爆发活性以及肠抗超氧阴离子活性和 SOD 显著提高了抗氧化能力。巧合的是，100mg/kg TTO 显著上调了虾肠道抗氧化相关基因（过氧化物酶-5）的相对表达。此外，研究发现 100mg/kg TTO 激活了虾的 toll-dorsal 途径，该途径通过上调 TNF-α和 IL-1 发挥与经典 NF-κB 途径相似的功能。最后，100mg/kg TTO 增加了氨氮胁迫后 iNOS 活性和 NO 含量，增强了非特异性免疫。结果表明，100mg/kg TTO 可显著提高罗氏沼虾的性能、抗氧化能力和抗氨氮应激能力。我们认为，这些机制可能归因于 TTO 通过 NF-κB 信号通路增强了罗氏沼虾的抗氧化能力和非特异性免疫。
