Batterham E S, Andersen L M, Baigent D R
NSW Agriculture, Wollongbar Agricultural Institute, New South Wales.
Br J Nutr. 1994 Mar;71(3):345-60. doi: 10.1079/bjn19940143.
The ileal digestibility of tryptophan for growing pigs was determined for cottonseed, meat-and-bone and soya-bean meals. Tryptophan in the food and digesta was measured by two analytical procedures (NaOH hydrolysis and colorimetric estimation (method 1) and LiOH hydrolysis and HPLC determination (method 2)). The results were respectively: cottonseed meal 0.46, 0.81; meat-and-bone meal 0.55, 0.65; soya-bean meal 0.74, 0.90. In the first experiment the values for method 1 were shown to be inapplicable to pigs. In a second experiment three tryptophan-deficient diets (0.05 g ileal digestible tryptophan/MJ digestible energy (DE)) were formulated using values from method 2 for cottonseed meal, meat-and-bone meal plus L-tryptophan and soya-bean meal respectively as the only sources of tryptophan in the diets. This experiment was terminated after 28 d as overall growth performance of the pigs was very low. A third experiment was conducted in a similar manner to Expt 2 except that the diets were formulated to 0.065 g ileal digestible tryptophan/MJ DE and growth responses and tryptophan retention were assessed over the 20-45 kg growth phase. Growth rates (g/d) of the pigs given the three diets were significantly different (P < 0.01): cottonseed meal 393, meat-and-bone meal plus L-tryptophan 531, soya-bean meal 437 (SED 39.0). Tryptophan retention (as a proportion of ileal digestible tryptophan intake) was significantly different (P < 0.05): cottonseed meal 0.51, meat-and-bone meal plus L-tryptophan 0.49, soya-bean meal 0.41. These results indicate (1) that the colorimetric technique for assessing tryptophan was inapplicable and (2) that ileal digestible values for tryptophan were not suitable for formulating diets containing heat-processed proteins, possibly due to absorption of some of the tryptophan in a form that was non-utilizable, and/or to underestimation of total tryptophan in the protein concentrates.
测定了棉籽粕、肉骨粉和豆粕对生长猪的色氨酸回肠消化率。采用两种分析方法（氢氧化钠水解和比色法测定（方法1）以及氢氧化锂水解和高效液相色谱法测定（方法2））测定食物和消化物中的色氨酸。结果分别为：棉籽粕0.46、0.81；肉骨粉0.55、0.65；豆粕0.74、0.90。在第一个实验中，方法1的值被证明不适用于猪。在第二个实验中，分别使用方法2得出的棉籽粕、添加L-色氨酸的肉骨粉和豆粕的值作为日粮中色氨酸的唯一来源，配制了三种色氨酸缺乏日粮（0.05 g回肠可消化色氨酸/MJ可消化能量（DE））。由于猪的总体生长性能非常低，该实验在28天后终止。第三个实验以与实验2类似的方式进行，不同之处在于日粮配制为0.065 g回肠可消化色氨酸/MJ DE，并在20 - 45 kg生长阶段评估生长反应和色氨酸保留情况。饲喂三种日粮的猪的生长速率（g/天）差异显著（P < 0.01）：棉籽粕组393，添加L-色氨酸的肉骨粉组531，豆粕组437（标准误39.0）。色氨酸保留率（占回肠可消化色氨酸摄入量的比例）差异显著（P < 0.05）：棉籽粕组0.51，添加L-色氨酸的肉骨粉组0.49，豆粕组0.41。这些结果表明：（1）用于评估色氨酸的比色技术不适用；（2）色氨酸的回肠可消化值不适用于配制含有热处理蛋白质的日粮，这可能是由于部分色氨酸以不可利用的形式被吸收，和/或蛋白质浓缩物中总色氨酸被低估。
