Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand.
J Anim Physiol Anim Nutr (Berl). 2012 Feb;96(1):148-58. doi: 10.1111/j.1439-0396.2011.01132.x. Epub 2011 Feb 15.
The response of cats to dietary sodium selenite (Na(2) SeO(3)) and organically bound selenium was studied in two separate studies with four cats per treatment and three levels of selenium supplementation (targets 1.0, 1.5 and 2.0 μg/g DM) for each Se source. Whole blood and plasma selenium concentrations and glutathione peroxidase (GPx) activity were determined at 7-time points across the 32-day study. Faeces were quantitatively collected during the last 8 days and urine was collected daily during both studies. The basal diet used had a low apparent faecal selenium absorption of 25.3 ± 3.0%. Daily faecal and urinary selenium excretion increased linearly with increasing selenium intake for both Se sources. Urinary selenium concentration of the cats fed the supplemented diets increased rapidly (∼2 days) and remained constant throughout the remainder of the study. Apparent faecal selenium absorption was high for both selenium sources (73.2% and 80.0%). Plasma, and to a lesser extent, whole blood selenium concentrations increased in a dose-dependent manner with supplementation. Whole blood and plasma GPx activity were highly variable and showed a variable response to dietary selenium intake. Cats closely regulate selenium homeostasis through increasing urinary excretion whilst faecal absorption remains unaffected.
本研究用 4 只猫进行了两项独立试验，每只猫接受 4 种处理，分别为两种硒源（亚硒酸钠（Na2SeO3）和有机硒），每个硒源设 3 个硒添加水平（目标硒添加量为 1.0、1.5 和 2.0μg/g 干物质）。在 32 天的试验中，共测定了 7 个时间点的全血和血浆硒浓度及谷胱甘肽过氧化物酶（GPx）活性。在两项试验的最后 8 天内，对粪便进行了定量收集，在整个试验期间每天收集尿液。基础日粮的表观粪便硒吸收率较低，为 25.3±3.0%。对于两种硒源，随着硒摄入量的增加，每日粪便和尿液硒排泄量呈线性增加。补充日粮后，猫的尿硒浓度迅速升高（约 2 天），并在试验剩余时间内保持稳定。两种硒源的表观粪便硒吸收率均较高（73.2%和 80.0%）。血浆硒浓度，在一定程度上还有全血硒浓度，随补充硒剂量的增加呈剂量依赖性增加。全血和血浆 GPx 活性变化较大，对膳食硒摄入量的反应也不同。猫通过增加尿硒排泄来严格调节硒的体内平衡，而不影响粪便硒的吸收率。
