PSVIII-A-5 - Effect of dosage level of fibrolytic enzymes from trichoderma reesei on in vitro degradation kinetics of intercropped silage from whole plant faba bean and whole oat plant

Abstract: The objectives of this study were to analyze the effect of dosage level of fibrolytic enzyme derived from Trichoderma Reesei (FETR) on in vitro rumen degradation kinetics of intercropped whole plant oat with whole plant faba bean silage in dairy cows. The oat and faba bean plants were intercropped and grown in three fields and were cut at the growth stage with whole oat plant at the soft dough stage and whole faba bean plant at the late pod stage. The rumen degradation kinetics was estimated using in vitro technique with rumen liquid from rumen cannulated lactating cows. The in vitro rumen degradation kinetics of dry matter (DM) and fibre (NDF, ADF) including degradation rate (Kd), lag time (T0), potentially degradable fraction (D), undegradable fraction (U), and effective degradable fractions and content (ED) were determined. The treatment design was a one-way structure with 5 dosage levels of fibrolytic enzyme (FETR: 0, 0.075, 0.15, 0.225, and 0.3 ml/L). The experimental design was a RCBD with the dosage level as a fixed effect and animals and in vitro run as random block effects. The data was analyzed using the Mixed model procedure in SAS 9.4 with the analysis RCBD model. The Orthogonal Polynomial Contrast of SAS was used to study the relationship between dosage levels and in vitro degradation kinetics. The results showed that the dosage level of FETR had no effect on lag time (T0 of DM). But the dosage level has a significantly linear effect (P < 0.05) on degradation rate (Kd of DM ranging from 13.92 to 15.70%/h), cubic effects (P < 0.05) on potential degradation fraction (D %) and undegradable fractions (U %). The dosage level tended to have cubic effects (P=0.077) with bypassed dry matter (BDM, ranging from 533 to 547 g/kg) and effective degradable dry matter (EDDM, ranging from 452 to 460 g/kg).