Schlegel P, Windisch W
Pancosma SA, Le Grand-Saconnex/GE, Switzerland.
J Anim Physiol Anim Nutr (Berl). 2006 Jun;90(5-6):216-22. doi: 10.1111/j.1439-0396.2005.00583.x.
The objective of this study was to quantify the bioavailability of zinc (Zn) from sulphate and glycinate as representatives of inorganic and organic zinc sources. The semi-synthetic basal diet contained 2 microg/g of native Zn and was fortified with pure sodium-phytate (8 g/kg) in order to simulate conditions of common cereal-based meals. The basal diet was supplemented with either 53 microg/g of Zn from sulphate (control) or 10 microg/g of Zn from either sulphate (ZnSulphate) or glycinate (ZnGly). Twenty-four (65)Zn-labelled, growing rats weighing 133 g were allotted to the three diets (eight animals per treatment) and were kept pair-fed to ZnSulphate for 15 days. Zn contents in blood plasma, femur and whole body, as well as, plasma alkaline phosphatase activities were reduced compared with control indicating a zinc deficiency in ZnSulphate and ZnGly treatment. This allowed their differentiation in zinc bioavailability. True absorption of dietary Zn was significantly higher in ZnGly than in ZnSulphate (51% vs. 44%) while losses of endogenous faecal Zn and urinary Zn were not affected to a quantitatively relevant extent (mean: 17% and 2% of intake). This resulted in a +30% significantly improved Zn retention for ZnGly (33% vs. 25%) and a lower severity on Zn deficiency symptoms compared with ZnSulphate. Metabolic utilization accounted for 95% of absorbed dietary Zn for both Zn sources. Overall, the bioavailability of zinc glycinate was significantly superior by 16% to zinc sulphate (49% vs. 42%), mainly because of a higher absorptive potential at presence of a strong anti-nutritive component (phytate) in the diet.
本研究的目的是量化作为无机和有机锌源代表的硫酸锌和甘氨酸锌的生物利用度。半合成基础日粮含有2微克/克的天然锌，并用纯植酸钠（8克/千克）强化，以模拟常见谷物类膳食的条件。基础日粮分别补充53微克/克的硫酸锌（对照）或10微克/克的硫酸锌（硫酸锌组）或甘氨酸锌（甘氨酸锌组）。将24只体重133克的（65）锌标记的生长大鼠分配到三种日粮组（每组处理8只动物），并与硫酸锌组配对饲养15天。与对照组相比，血浆、股骨和全身的锌含量以及血浆碱性磷酸酶活性均降低，表明硫酸锌组和甘氨酸锌组存在锌缺乏。这使得它们在锌生物利用度上得以区分。甘氨酸锌组膳食锌的真吸收率显著高于硫酸锌组（51%对44%），而内源性粪便锌和尿锌的损失在定量上没有受到显著影响（平均：摄入量的17%和2%）。这导致甘氨酸锌组的锌保留率显著提高30%（33%对25%），与硫酸锌组相比，锌缺乏症状的严重程度更低。两种锌源的代谢利用率均占吸收膳食锌的95%。总体而言，甘氨酸锌的生物利用度比硫酸锌显著高16%（49%对42%），主要是因为在日粮中存在强抗营养成分（植酸盐）的情况下，其吸收潜力更高。
