Comparison of protein digestibility of rumen undegraded protein estimated by an enzymatic and mobile bag method: feeds for ruminants and anaerobic fungus

Crude protein digestibility (CPD) of rumen undegraded protein (RUP) was estimated in vitro with pancreatin method (PM). In parallel, total protein digestibility of rumen undegraded protein in the digestive tract was measured in situ with mobile bag technique (MB). Totally, 55 feed samples including forage, silage, straw and various meals were analyzed. Samples were incubated in the rumen for 16 h and then tested with MB and PM methods. Results obtained from both techniques were compared and equation of linear regression was counted: (CPDPM=7.47+0.95 CPDMB; r2=0.861). Digestibility of rumen fungal protein was estimated with both techniques. With mobile bag technique the CPD of polycentric fungus Orpinomyces joyonii A4 was 78.08±3.08% and the crude protein digestibility measured with pancreatin method was 79.48±1.66%.