Bergner H, Schwandt H, Krüger U
Sektion Tierproduktion und Veterinärmedizin, Humboldt-Universität zu Berlin.
Arch Tierernahr. 1990 Jul;40(7):569-82. doi: 10.1080/17450399009428407.
60 Wistar rats (5 animals/group) received 12 different feedstuffs over a period of 7 days and were simultaneously labelled with 15N (orally by means of 15NH4Cl in the feed). In the subsequent 5 days faeces were collected in order to determine the apparent and true digestibility of crude protein. On the 13th experimental day the animals were killed 3 hours after the intake of half the daily ration and the atom-% 15N excess (15N') was determined in the TCA-soluble and TCA-precipitable fractions of the blood plasma and the digesta of the 2nd and 3rd thirds of the small intestine. Precaecal N-absorption was calculated with the help of the quotient [formula: see text] the blood plasma and the digesta The following values (in %) were registered in comparison to true N-digestibility (in the following in brackets): casein = 95.8 (99.2), whole egg = 92.1 (97.5), fish meal = 85.8 (93.4), dried skimmed milk = 98.4 (96.1), soybean meal = 79.6 (90.6), assay protein = 94.2 (98.9), wheat = 92.9 (90.7), barley = 84.3 (84.8), yeast, grown on molasses = 85.6 (87.2), yeast, grown on whey = 86.1 (88.5), biomass of liquid manure = 43.6 (68.9), activated sludge = 54.4 (64.1). One can conclude that the isotope dilution technique demonstrated here as an evaluation method is very well suited for the characterization of the N-digestibility of a feedstuff in the small intestine.
60只Wistar大鼠（每组5只）在7天内接受12种不同的饲料，并同时用15N进行标记（通过饲料中的15NH4Cl口服）。在随后的5天内收集粪便，以测定粗蛋白的表观消化率和真消化率。在实验的第13天，动物在摄入一半日粮3小时后处死，测定血浆以及小肠中、后三分之一段食糜中三氯乙酸可溶性和三氯乙酸沉淀部分的原子百分比过量15N（15N'）。借助公式[公式：见原文]计算盲肠前氮吸收量，该公式涉及血浆和食糜。与真氮消化率相比（以下括号内为真氮消化率），记录到以下数值（%）：酪蛋白 = 95.8（99.2），全蛋 = 92.1（97.5），鱼粉 = 85.8（93.4），脱脂奶粉 = 98.4（96.1），豆粕 = 79.6（90.6），分析用蛋白质 = 94.2（98.9），小麦 = 92.9（90.7），大麦 = 84.3（84.8），以糖蜜为培养基生长的酵母 = 85.6（87.2），以乳清为培养基生长的酵母 = 86.1（88.5），厩液生物质 = 43.6（68.9），活性污泥 = 54.4（64.1）。可以得出结论，这里展示的作为一种评估方法的同位素稀释技术非常适合表征饲料在小肠中的氮消化率。
