低硒大鼠对紫阳高硒小麦硒的相对生物利用率

THE RELATIVE BIOAVAILABILITY OF SELENIUM IN ZIYANG HIGH-Se WHEAT TO SELENIUM-DEFICIENT RATS

本文用耗竭—补充—耗竭的设计,以克山病病区低硒粮饲料(含硒0.006ppm)喂养大鼠6周后,观察了补充紫阳高硒小麦(含硒1.175ppm)或亚硒酸钠,使饲料含硒分别为0.219和0.223ppm时,以及停止补硒后,大鼠组织和血液硒水平和谷胱甘肽过氧化物酶(GSH-px)活性的变化,并评估了紫阳高硒小麦的相对生物利用率。结果表明,以血浆、红细胞、肾、肝和心肌硒水平为指标时,高硒小麦硒的平均生物利用率(补硒2、4和6周时)与亚硒酸钠相似,其相对生物利用率分别为98％,104％,100％,96％和101％(亚硒酸钠为100％);而以心肌和红细胞GSH-Px活性为指标时,其生物利用率(90％和70％)低于亚硒酸钠。但在补硒的各时期,血液和各组织对高硒小麦硒的相对生物利用率不尽相同。此外,在停止补硒3周时,高硒小麦维持心、肝和红细胞硒水平以及心肌GSH-Px活性的作用优于亚硒酸钠。

A three-phase depletion/repletion/depletion feeding study was designed to investigate the changes of Se levels and glutathione peroxidase (GSH-Px) activities in tissues and blood in rats fed for 6 weeks low-Se diet (6 ppb Se) from a Keshan disease area during the supplementations of Se as Ziyang high-Se wheat (1.175 ppm Se) or sodium selenite (dietary Se 219 and 223 ppb respectively) and after the supplements were discontinued, and to evaluate the relative bioavailability of Se in the wheat. The resalts showed that the average bioavailability of Se in high-Se wheat derived from the values at wk 2, 4 and 6 of supplement was close to that in selenite when plasma, erythrocyte, kidney, liver and cardiac Se contents were used as the response criteria, the relative bioavailabilities being 98%, 104%,100%,96% and 101% (sodium selenite = 100%) respectively. The bioavailability was lower for Se in high-Se wheat (70% or 90%) than for selenite when estimated by erythro-cyte or cardiac GSH-Px activities. However, the bioavailabilities of high-Se wheat Se in various tissues were not all the same at different stages of supplement. In addition, the effect of Se in high-Se wheat in maintaining either Se levels in heart, liver and erythrocyte or GSH-Px activity in heart was superior to that of selenite 3 weeks after the Se supplements were withdrawn.