Wünsche J, Hennig U, Meinl M, Kreienbring F, Bock H D
Arch Tierernahr. 1982 May;32(5-6):337-48. doi: 10.1080/17450398209421023.
In N-balance experiments with growing pigs (40-60 kg live weight) investigations were made whether lysine or isoleucine that is infused into the caecum can be absorbed there and to what extent these amino acids in that case can be utilised by the animal for protein synthesis. The pigs either received basic rations with insufficient lysine or isoleucine resp. (negative control group) or the amounts of lysine and isoleucine lacking to meet the requirement were supplemented with the feed (positive control group) or continuously infused into the caecum with the help of caecal infusion cannulae (test group). In the experiments with lysine the animals in the negative control group and in the test group showed considerably lower N-balances than the positive control group. There were no differences as regards the apparent digestibility of lysine between the positive control group and the test group. The urine of the test group contained distinctly more NH3. This shows clearly that lysine that is infused into the caecum cannot be utilised by the pigs, it is, on the contrary, microbially decomposed, the nitrogen is chiefly absorbed as NH3 and excreted in urine. As regards isoleucine, the deficit brought about with the basic ration was insufficient in order to achieve significant differences between the N-balance values of the groups so that unambiguous statements on the absorption and utilisation of isoleucine infused into the caecum cannot be made. Concerning apparent digestibility of isoleucine and the NH3 content of the urine, the results of the isoleucine experiments were similar to those in the lysine experiments. According to our N-balance experiments the isoleucine requirement of pigs indicated in relevant literature as 5.6 g/kg dry matter of the feed is by far too high. It should be limited to 3.5 or a maximum of 4.0 g isoleucine per kg dry matter of the feed.
在对生长猪（体重40 - 60千克）进行的氮平衡实验中，研究了注入盲肠的赖氨酸或异亮氨酸是否能在盲肠被吸收，以及在这种情况下这些氨基酸能在多大程度上被动物用于蛋白质合成。这些猪要么摄入赖氨酸或异亮氨酸含量不足的基础日粮（分别为阴性对照组），要么用饲料补充满足需求所缺乏的赖氨酸和异亮氨酸量（阳性对照组），要么借助盲肠灌注插管持续注入盲肠（试验组）。在赖氨酸实验中，阴性对照组和试验组的动物氮平衡明显低于阳性对照组。阳性对照组和试验组在赖氨酸的表观消化率方面没有差异。试验组的尿液中明显含有更多的NH₃。这清楚地表明，注入盲肠的赖氨酸不能被猪利用，相反，它会被微生物分解，氮主要以NH₃的形式被吸收并随尿液排出。至于异亮氨酸，基础日粮造成的不足程度不足以使各组的氮平衡值产生显著差异，因此无法对注入盲肠的异亮氨酸的吸收和利用做出明确的说明。关于异亮氨酸的表观消化率和尿液中的NH₃含量，异亮氨酸实验的结果与赖氨酸实验的结果相似。根据我们的氮平衡实验，相关文献中指出的猪对异亮氨酸的需求量为每千克饲料干物质5.6克，这远远过高。应将其限制在每千克饲料干物质3.5克或最多4.0克异亮氨酸。
