PREDICTION OF IN-SITU RUMEN ESCAPE PROTEIN FROM IN-VITRO INCUBATION WITH PROTEASE FROM STREPTOMYCES-GRISEUS

Research was performed to determine in vitro the amount of rumen escap e protein in mainly concentrate feedstuffs by incubation with a proteo lytic enzyme preparation of Streptomyces griseus, with 24 feed samples with known in situ crude protein degradation characteristics, A close correlation (R(2) = 0.75) was found between the percentage of escape protein, calculated from the in situ and the in vitro methods. However , the percentage escape protein in situ could be estimated with a grea ter accuracy (R(2) = 0.80) using the undegraded fraction determined in vitro after 24 h incubation, Expressing escape protein as g kg(-1) DM instead of a percentage, further improved the correlation with the am ount of escape protein in situ (R(2) = 0.95). The amount of escape pro tein in situ could be estimated with similar accuracy from the undegra ded crude protein fraction determined in vitro after 24 h incubation ( R(2) = 0.92). Estimation of the amount of escape protein in situ did n ot improve with pre-incubation of the samples with amylase and carbohy drate degrading enzymes.