Iske Cayla J, Johnson Anna K, Kappen Kelly L, Deever Roni M, Morris Cheryl L
Department of Animal Science, Iowa State University, Ames, IA, USA.
Omaha's Henry Doorly Zoo and Aquarium, Omaha, NE, USA.
Transl Anim Sci. 2025 May 21;9:txaf049. doi: 10.1093/tas/txaf049. eCollection 2025.
The brain is particularly susceptible to oxidative stress (OS) and damage to membranes is associated with learning and memory decline, impacting animal welfare. Vitamin E is an antioxidant which crosses the blood-brain barrier. Our objectives were to assess the impact of dietary vitamin E concentrations (20, 90, and 400-ppm) on markers of OS, maze learning performance (MLP), and anxious behaviors in 3-wk old Long-Evans rats. Vitamin E concentrations, antioxidant enzymes (superoxide dismutase [SOD] and glutathione peroxidase [GPx]), and oxidative protein damage (protein carbonyls [PC]) were measured in plasma or serum. Lipid damage (thiobarbituric acid reactive substances [TBARS]) was measured in serum and hippocampus. Anxious behaviors, including freezing and grooming, and MLP were assessed in an eight-arm radial maze over 5 weeks. Activity of SOD was lower ( = 0.002), and PC concentrations were higher ( = 0.022) in the 400-ppm group (1.0 U/mL; 0.7 nmol/mg) compared to the 20 (2.9 U/mL; 0.5 nmol/mg) and 90 (1.7 U/mL; 0.5 nmol/mg). Plasma vitamin E increased ( < 0.050) with dietary treatment and SOD decreased as plasma vitamin E increased (R = 0.46; = 0.002) but PC (R = 0.16; = 0.090) concentrations tended to increase with plasma vitamin E. Dietary treatment did not impact ( > 0.050) maze learning performance. Rats fed 20 ppm vitamin E exhibited greater freezing frequency and duration ( < 0.001) compared to other treatment groups, indicating heightened anxiety. The 400-ppm group exhibited lowest grooming frequency and duration ( < 0.001), possibly indicating less anxiousness. Working memory errors increased with serum TBARS concentrations (R = 0.26; = 0.033). In conclusion, higher dietary vitamin E concentrations reduced anxious behaviors, but did not alter MLP and was correlated with increased OS. These results suggest high concentrations of dietary vitamin E are not beneficial for rat welfare.
大脑特别容易受到氧化应激（OS）的影响，而膜损伤与学习和记忆衰退有关，会影响动物的健康。维生素E是一种能穿过血脑屏障的抗氧化剂。我们的目标是评估日粮中维生素E浓度（20、90和400 ppm）对3周龄Long-Evans大鼠的氧化应激标志物、迷宫学习性能（MLP）和焦虑行为的影响。在血浆或血清中测量维生素E浓度、抗氧化酶（超氧化物歧化酶[SOD]和谷胱甘肽过氧化物酶[GPx]）以及氧化蛋白质损伤（蛋白质羰基[PC]）。在血清和海马体中测量脂质损伤（硫代巴比妥酸反应性物质[TBARS]）。在5周内通过八臂放射状迷宫评估包括僵住和梳理在内的焦虑行为以及MLP。与20 ppm（2.9 U/mL；0.5 nmol/mg）和90 ppm（1.7 U/mL；0.5 nmol/mg）组相比，400 ppm组的SOD活性较低（P = 0.002），PC浓度较高（P = 0.022）（1.0 U/mL；0.7 nmol/mg）。随着日粮处理，血浆维生素E升高（P < 0.050），且随着血浆维生素E升高SOD降低（R = 0.46；P = 0.002），但PC浓度（R = 0.16；P = 0.090）倾向于随着血浆维生素E升高。日粮处理对迷宫学习性能没有影响（P > 0.050）。与其他处理组相比，饲喂20 ppm维生素E的大鼠表现出更高的僵住频率和持续时间（P < 0.001），表明焦虑加剧。400 ppm组表现出最低的梳理频率和持续时间（P < 0.001），可能表明焦虑程度较低。工作记忆错误随着血清TBARS浓度增加（R = 0.26；P = 0.033）。总之，日粮中较高的维生素E浓度可减少焦虑行为，但不会改变MLP，且与氧化应激增加相关。这些结果表明日粮中高浓度的维生素E对大鼠健康并无益处。
