Degradation in the rumen of proteins of 2 legumes: soybean meal and field pea.

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.

[Relationship of nitrogen degradability of feed concentrates in the rumen and its digestibility in the intestine, and several biochemical criteria]. / Relations entre la dégradabilité de l'azote des aliments concentrés dans le rumen et sa digestibilité dans l'intestin, et certains critères biochimiques.

Estimation of intestinal nitrogen digestibility was related to acid detergent-insoluble nitrogen (ADIN) or pepsin-insoluble nitrogen (IP). Feedstuffs were then classified according to their in sacco nitrogen degradability in the rumen and ADIN or IP.