Abstract
The aim of the study was to determine the effect of an exogenous fibrolytic enzyme (EFE) on the ruminal disappearance of dry matter (DM), neutral detergent fibre (NDF), crude protein (CP) and on the microbial protein synthesis (MPS) in sheep of a milled substrate consisting of a 50 : 50 mixture of lucerne hay (LH) and wheat straw (WS). Four cannulated Döhne-Merino sheep were randomly assigned to two groups in a 2 x 2 cross-over experiment. Additional to the in situ study, the effects of an exogenous fibrolytic enzyme (EFE) on the in vitro gas production (GP) and ANKOM digestion systems on the mixture of milled LH and WS were determined. The substrate was pre-treated with distilled water (control) or EFE (treatment) 12 hours prior to incubation to allow interaction between the substrate and enzyme. Adding EFE significantly improved the in vitro cumulative gas production (GP), but it did not affect the in vitro MPS measured as purine derivates of the GP residues. The enzyme significantly increased the in vitro DM and NDF disappearances after 36 hours. However, the in situ disappearances of DM, NDF and CP of the roughage mixture were not affected by the EFE. Further, the in situ MPS was increased significantly with the EFE treatment of the mixed substrate. It is concluded that the improved ruminal digestion of DM, NDF and CP is not only due to direct enzyme hydrolysis, but also due to the improvement of MPS.Keywords: Fibre digestion, in vitro and in situ digestion, ruminants
Highlights
Ruminant production systems are based on the utilization of forages, with fibrous material being important for salivation, rumen buffering and efficient production of rumen end products
The effect of exogenous fibrolytic enzyme (EFE) on gas production (GP) is indicated in Figure 1(a) as the cumulative gas produced over a 48 h incubation period
Pre-treatment of a mixed substrate with EFE resulted in an improved cumulative GP (P 0.05) on the microbial protein synthesis (MPS) with EFE treatment was observed (Figure 1)
Summary
Ruminant production systems are based on the utilization of forages, with fibrous material being important for salivation, rumen buffering and efficient production of rumen end products. Less than 65% of the fibrous plant cell walls are efficiently digested in the total digestive tract of ruminants (Van Soest, 1994). With 40% – 70% of the forage DM consisting of cell walls, it would be important to improve ruminal fibre digestion. In the past 10 to 15 years, the use of EFE as feed additives has shown promise at hydrolyzing plant cell walls (Beauchemin et al, 2004). Their biological response in ruminant systems is difficult to predict because of inconsistent results (Beauchemin et al, 2003). The aim of the study was to determine the EFE effect on the DM, CP and NDF digestion of a mixture of lucerne hay and wheat straw (50 : 50) to improve MPS
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
