Aufrère J, Graviou D, Michalet-Doreau B
INRA-Theix, Station de Recherches sur la Nutrition des Herbivores, Unité Valeur Alimentaire, Saint-Genès-Champanelle, France.
Reprod Nutr Dev. 1994;34(5):483-90. doi: 10.1051/rnd:19940509.
Ruminal protein degradation of soybean meal and field pea were compared using 2 analytical methods: in situ and a laboratory analysis with a proteolytic enzyme extracted from Streptomyces griseus. The degradation of total nitrogen in nylon bags of the feeds was measured between 0 and 48 h in the rumen of 2 cows (theoretical degradability: 70.0% for soybean meal and 94.7% for field pea). Electrophoresis of proteins of feeds and in situ residues, in sodium dodecyl sulfate-polyacrylamide gel (SDS-PAGE) showed that both species have the same type of proteins (7S and 11S) which were degraded in a similar manner in the rumen. The 7S fraction was degraded rapidly whereas the 11S fraction was more resistant. The electrophoretic profiles showed that protein components were less degraded after enzymatic than in situ degradation. In the supernatant after enzymatic hydrolysis, protein and peptides were found in large concentrations and alpha-amino nitrogen and ammonia in low concentrations. It was difficult to simulate the in vitro activity of enzyme complexes in the rumen and the results must be confirmed by direct measurement of the rumen liquid.
原位法和使用从灰色链霉菌中提取的蛋白水解酶进行的实验室分析。在2头奶牛的瘤胃中，测定了0至48小时内饲料尼龙袋中总氮的降解情况（理论降解率：豆粕为70.0%，豌豆为94.7%）。在十二烷基硫酸钠-聚丙烯酰胺凝胶（SDS-PAGE）中对饲料和原位残留物的蛋白质进行电泳分析，结果表明两种饲料具有相同类型的蛋白质（7S和11S），它们在瘤胃中的降解方式相似。7S组分降解迅速，而11S组分更具抗性。电泳图谱显示，酶解后蛋白质成分的降解程度低于原位降解。酶解后的上清液中，蛋白质和肽的浓度较高，而α-氨基氮和氨的浓度较低。很难在体外模拟瘤胃中酶复合物的活性，结果必须通过直接测量瘤胃液来证实。
