1. Ruminal Crude Protein Degradation Determined in Sacco and by Co-Incubation of Streptomyces griseus Protease and Carbohydrases.
- Author
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Okon, Paul, Wensch-Dorendorf, Monika, Bachmann, Martin, von Soosten, Dirk, Meyer, Ulrich, Greef, Jörg-Michael, Dänicke, Sven, and Zeyner, Annette
- Subjects
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DISTILLERY by-products , *STREPTOMYCES griseus , *RAPESEED meal , *PROTEOLYSIS , *CARBOHYDRASES - Abstract
Simple Summary: Ruminal protein degradation of seven feedstuffs was estimated in sacco and in vitro by using a protease assay. In sacco protein degradation data were used as reference. The accuracy of the protease assay is reduced by two methodological aspects. During in vitro incubation, microbial activity induced by microbial colonization of the feedstuff may increase, requiring antibiotic solutions in protease assays. The protease alone cannot sufficiently hydrolyze protein–carbohydrate complexes. Therefore, a carbohydrase of fiber- or starch-hydrolyzing activity was added to the protease assay as a simultaneous incubation. The antibiotic solution reduced protein degradation by protease. The antibiotic solution is recommended to prevent microbial activity and improve standardization of the protease assay. Differences between in sacco and in vitro degradation data were not essentially reduced by additional carbohydrases. Unfavorable incubation conditions and the inhibitory effect of protease on the carbohydrase activity during simultaneous incubation may be responsible for the insufficient hydrolysis of protein–carbohydrate complexes by the carbohydrases. It does not seem promising to incubate protease and carbohydrase simultaneously. The objectives of the study were to examine the effect of an antibiotic solution applied in the Streptomyces griseus protease method (SGPM) and the effect of carbohydrases in SGPM on the effective crude protein (CP) degradation (ED) with reference to in sacco ED. For this purpose, the ruminal CP degradation of rapeseed meal, dried distillers' grains with solubles, wheat grain, corn grain, corn silage, grass silage and partial crop field pea silage was determined in sacco using three rumen-fistulated dairy cows and in vitro using SGPM. The impact of the antibiotic solution on CP degradation by S. griseus protease was investigated by supplementing SGPM with Penicillin–Streptomycin solution to reduce microbial mass proliferation during incubation. The carbohydrase α-amylase or Viscozym® L (cell wall-degrading enzyme mixture) was added to the SGPM at four different doses simultaneously as a co-incubation to improve feed protein accessibility. For most feedstuffs, ED was lower when the antibiotic solution was used in SGPM (p < 0.05). The use of an antibiotic solution in the SGPM is recommended to standardize the SGPM. The in sacco ED values were significantly underestimated by the SGPM and by the SGPM with co-incubated carbohydrase (p < 0.05). Co-incubation of S. griseus protease and carbohydrase was not successful in reducing the differences to the in sacco CP degradation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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