Krawielitzki K, Kreienbring F, Schadereit R, Völker T
Universität Rostock, Agrarwissenschaftliche Fakultät, Institut für umweltgerechte Tierhaltung, Germany.
Arch Tierernahr. 1995;48(1-2):37-51. doi: 10.1080/17450399509381826.
The time course of AA digestion, AA balance (sV AS), and AA absorption (wV AS) was estimated on growing rats (Wistar rats, LW = 124 g) in different sections of the intestinal tract using the combination of 15N tracer and TiO2 marker techniques. The animals received once a diet of 15N labelled wheat and yeast as protein sources supplemented by TiO2 as a marker. Up to 6 h after feeding the amino acid composition the 15N excess and the TiO2 content in the digesta of stomach, small and large intestine were determinated in the relation of amino acids resp. of 15N labelled amino acids to the marker. In addition the content of amino acids and the 15N excess of these amino acids were estimated in plasma. From these data the disappearance rates and the relation of exogenous to endogenous amino acids as well as the sV and the wV values of the different amino acids were calculated for the different gut sections. The following results were obtained: The relative disappearance rate for N and TiO2 marker out of the stomach went approximately parallel but with a delay for TiO2 of about 30 minutes. The AA composition of the stomach content, the small and the large intestine content did not vary in dependence of the time. The AA composition of the stomach digesta was nearly identical to that of the diet, while that of the small intestine was between exogenous AA composition (feed) and endogenous AA composition (digesta on protein free feeding). AA composition of the large intestine digesta showed quite big differences (bacterial AA break down and AA synthesis). Considering a delay time (small intestine: 1 h, large intestine: 4 h) the exogenous portion of the different AA remained constant in both of these intestinal sections during the whole experimental time. The exogenous AA part varied for small intestine digesta between 31 and 69% (mean value: 41%), and for large intestine digesta between 13 and 39% (mean value: 22%). The sV AS values in the small intestine (AA balance resp. precaecal digestibility) differed from 61% (threonine) to 86% (proline) with an average of 73.4 +/- 7.4%, those for wV AS (AA absorption) from 81% (lysine) to 94% (proline) with an average of 88.1 +/- 4.1%. There were significant differences between AA, but they are negligible for practical purposes.(ABSTRACT TRUNCATED AT 400 WORDS)
采用¹⁵N示踪技术和二氧化钛（TiO₂）标记技术相结合的方法，对生长大鼠（Wistar大鼠，体重124 g）肠道不同部位的氨基酸（AA）消化过程、AA平衡（sV AS）及AA吸收（wV AS）的时间进程进行了评估。动物一次性摄入以¹⁵N标记的小麦和酵母作为蛋白质来源，并添加TiO₂作为标记物的日粮。喂食氨基酸组合物后6小时内，测定胃、小肠和大肠消化物中¹⁵N过量及TiO₂含量与氨基酸（分别针对¹⁵N标记氨基酸与标记物）的关系。此外，还测定了血浆中氨基酸含量及这些氨基酸的¹⁵N过量情况。根据这些数据，计算出不同肠道段中不同氨基酸的消失率、外源氨基酸与内源氨基酸的关系以及sV和wV值。得到以下结果：胃中N和TiO₂标记物的相对消失率大致平行，但TiO₂的消失延迟约30分钟。胃内容物、小肠和大肠内容物的AA组成不随时间变化。胃消化物的AA组成与日粮几乎相同，而小肠的AA组成介于外源AA组成（饲料）和内源AA组成（无蛋白饲料喂养时的消化物）之间。大肠消化物的AA组成显示出很大差异（细菌对AA的分解和AA合成）。考虑到延迟时间（小肠：1小时，大肠：4小时），在整个实验期间，不同AA的外源部分在这两个肠道段中保持恒定。小肠消化物的外源AA部分在31%至69%之间变化（平均值：41%），大肠消化物的外源AA部分在13%至39%之间变化（平均值：22%）。小肠中的sV AS值（AA平衡即盲肠前消化率）从61%（苏氨酸）到86%（脯氨酸）不等，平均为73.4±7.4%，wV AS值（AA吸收）从81%（赖氨酸）到94%（脯氨酸）不等，平均为88.1±4.1%。不同AA之间存在显著差异，但在实际应用中可忽略不计。（摘要截取自400字）
