Selenium (Se) deficiency is a problem widely encountered in humans and terrestrial livestock production with increasing attention also in aquaculture. Se supports the antioxidant system, which becomes especially important during stressful conditions. In the present study, the effect of Se-supplementation in broodstock and fry diets on the performance and antioxidant metabolism of rainbow trout fry under acute hypoxia was investigated. Rainbow trout broodstock were fed plant-ingredient based diets either without any Se-supplementation (Se level: 0.3 mg/kg) or supplemented with Se supplied as sodium selenite or as hydroxy-selenomethionine (Se level: 0.6 mg/kg respectively) for 6 months prior to spawning. The progenies were subdivided into three triplicate feeding groups and fed diets with similar Se levels compared to the parental diets, resulting in a 3x3 factorial design. After 11 weeks of feeding, the fry were either sampled or subjected to a hypoxic stress challenge. One hundred fish were transferred to tanks containing water with a low oxygen level (1.7 ± 0.2 ppm) and monitored closely for 30 min. When a fish started to faint it was recorded and transferred back to normoxic water. Direct fry feeding of the hydroxy-selenomethionine supplemented diet improved the resistance towards the hypoxic stress. On the contrary, fry originating from parents fed Se-supplemented diets showed a lower stress resistance compared to fry originating from parents fed the control diet. Fry subjected to hypoxia showed elevated oxidative stress with reduced glutathione (GSH) levels and increased isoprostanes (IsoP) and phytoprostanes (PhytoP) levels produced by lipid peroxidation of polyunsaturated fatty acids (PUFA), arachidonic and α-linolenic acids respectively. Increased mRNA expression of transcription factors (nrf2, nfκb, keap1X2) and decreased mRNA expression of antioxidant enzymes (trxr, sod, gstπ) indicated a transcriptional regulation of the antioxidant response. In stressed fry, the mRNA expression of several antioxidant genes including gr, msr and gstπ was found to be higher when fed the control diet compared to the sodium selenite treatment, with a contrary effect for parental and direct Se nutrition on gpx. The long-term parental effect becomes of greater importance in stressed fry, where more than half of the genes were significantly higher expressed in the control compared to the selenite supplemented group.

硒缺乏是人类和陆地牲畜生产中普遍遇到的问题，水产养殖也日益受到关注。硒支持抗氧化系统，这在压力条件下尤为重要。在本研究中，研究了在低氧条件下，在亲鱼和鱼苗日粮中添加硒对虹鳟鱼苗的性能和抗氧化代谢的影响。向虹鳟亲鱼饲喂基于植物成分的饮食，不添加任何硒（硒含量：0.3 mg / kg），或补充以亚硒酸钠或羟基硒代蛋氨酸提供的硒（分别为硒含量：0.6 mg / kg）6次产卵前几个月。将子代分为三个重复的喂养组，并饲喂与亲代饮食相比硒水平相似的饮食，产生3x3阶乘设计。喂食11周后，将鱼苗取样或进行低氧胁迫攻击。将一百条鱼转移到装有低氧水平（1.7±0.2 ppm）的水的水箱中，并严密监视30分钟。当一条鱼开始晕倒时，将其记录下来并转移回常氧水中。直接油炸补充羟基硒代蛋氨酸的饮食可以改善对低氧胁迫的抵抗力。相反，与饲喂对照饮食的父母的鱼苗相比，饲喂含硒饮食的父母的鱼苗显示出较低的抗逆性。缺氧的鱼苗显示出氧化应激升高，谷胱甘肽（GSH）含量降低，多不饱和脂肪酸（PUFA），花生四烯酸和α-亚麻酸的脂质过氧化产生的异前列腺素（IsoP）和植物前列腺素（PhytoP）含量升高。转录因子的mRNA表达增加（nrf2，nfκb，keap1X2）和抗氧化酶（trxr，sod，gstπ）的mRNA表达下降表明抗氧化反应的转录调控。在应激鱼苗中，饲喂对照饮食时，与亚硒酸钠相比，几种抗氧化剂基因（包括gr，msr和gstπ）的mRNA表达更高，这对亲本和直接硒营养对gpx的影响相反。长期父母效应在应激鱼苗中变得更加重要，与添加亚硒酸盐的组相比，对照组中超过一半的基因表达明显较高。