Akdeniz University, Agriculture Faculty, Department of Agricultural Biotechnology, Division of Animal Biotechnology, 07058 Antalya, Turkey.
Faculty of Agriculture, Department of Agricultural Biotechnology, Ondokuz Mayıs University, Samsun, Turkey.
Comp Biochem Physiol A Mol Integr Physiol. 2021 Dec;262:111060. doi: 10.1016/j.cbpa.2021.111060. Epub 2021 Aug 26.
Hypoxia and hyperoxia are disparate stressors which can have destructive influences on fish growth and physiology. It is yet to be determined if hypoxia and hyperoxia have a cumulative effect in aquatic ecosystems that affect biological parameters in fish, and to understand if this is associated with gene expression. Here we address whether growth performance and expressions of growth, immune system and stress related genes were affected by hypoxia and hyperoxia in fish. Rainbow trout was chosen as the study organism due to its excellent service as biomonitor. After an acclimatization period, fish were exposed to hypoxia (4.0 ± 0.5 ppm O), normoxia (7.5 ± 0.5 ppm O) and hyperoxia (12 ± 1.2 ppm O) for 28 days. At 6 h, 12 h, 24 h, 48 h, 72 h and 28 days, samples were collected. Hypoxia and hyperoxia negatively affected weight gain (WG), specific growth rate (SGR), survival rate (SR) and feed conversion ratio (FCR). The best WG, SGR, SR and FCR values occurred in fish exposed to normoxia, whereas hypoxia was most suppressive on growth and hyperoxia showed intermediate suppression of these parameters. Gene expression analyses were performed in liver and results revealed that long term exposure caused reduced growth hormone-I (GH-I) and insulin like growth factor I-II (IGF I-II) levels in both hypoxia and hyperoxia-treated fish. Heat shock protein (HSP70) levels increased in both hypoxia and hyperoxia treatment, and both exposures caused elevation of leptin (LEP) expression in long-term exposure. Overall data indicate that both hypoxia and hyperoxia cause stress in rainbow trout and negatively affects growth parameters.
缺氧和富氧是两种不同的应激源，它们会对鱼类的生长和生理产生破坏性影响。目前还不清楚缺氧和富氧在水生生态系统中是否会产生累积效应，从而影响鱼类的生物参数，也不清楚这是否与基因表达有关。在这里，我们研究了缺氧和富氧是否会影响鱼类的生长性能以及生长、免疫系统和应激相关基因的表达。选择虹鳟作为研究对象，因为它是生物监测的良好选择。在适应期后，鱼被暴露在缺氧（4.0±0.5 ppm O）、常氧（7.5±0.5 ppm O）和富氧（12±1.2 ppm O）中 28 天。在 6 h、12 h、24 h、48 h、72 h 和 28 d 时采集样本。缺氧和富氧都对增重（WG）、特定生长率（SGR）、存活率（SR）和饲料转化率（FCR）产生负面影响。在常氧暴露的鱼中，WG、SGR、SR 和 FCR 值最佳，而缺氧对生长的抑制作用最大，富氧对这些参数的抑制作用居中。在肝脏中进行了基因表达分析，结果表明，长期暴露导致缺氧和富氧处理的鱼中的生长激素 I（GH-I）和胰岛素样生长因子 I-II（IGF I-II）水平降低。热休克蛋白（HSP70）水平在缺氧和富氧处理中均升高，两种暴露均导致长期暴露时瘦素（LEP）表达升高。总的来说，数据表明缺氧和富氧都会使虹鳟鱼产生应激，从而对生长参数产生负面影响。
