Kinetic parameters of ruminal degradation in vitro with combinations of exogenous enzymes in diets of production systems simulated

Abstract

SUMMARY This study evaluated the effects of eight combinations of three exogenous enzymes with fibrolytic activity (FIB), amylolytic activity (AMZ), and proteolytic activity (PRO) on the accumulated gas production (PG) and kinetic parameters in simulated fermentations in two diet production systems using the in vitro gas production technique. In experiment 1, ruminal fluid was obtained from two Santa Ines sheep, cannulated in the rumen, kept in a feedlot and fed a diet containing a roughage:concentrate ratio of 20:80. In experiment 2, the ruminal fluid was obtained from two Santa Ines sheep, cannulated in the rumen, and kept on pasture (Brachiaria brizantha cv. Marandu). The accumulated gas production was measured during a 96-hour incubation, measured at 18 different time points. After incubation, the pH, dry matter degradability, organic matter in vitro digestibility, digestibility of neutral detergent insoluble fiber, metabolizable energy, partitioning factor, gas yield, short chain fatty acids and microbial protein production were determined. In the in vitro fermentation using the feedlot diet, the increased use of fibrolytic enzymes increased PG and improved the profile characteristics and kinetic parameters of the fermentation, regardless of the combination with other enzymes. In the in vitro fermentation using the forage diet, increased fibrolytic enzymes also increased PG, with improvements in the kinetic parameters and the profile of the fermentation, independent of the use of the other enzymes. The addition only of fibrolytic enzymes has major potential to optimize the use of feedlot diets as well of forage in ruminant feed.

Effect of combining exogenous fibrolytics enzymes supplementation with alkali and acid pre-treatments on wheat straw hydrolysis and ruminal fermentation

“…As enzyme doses are unequally spaced the Proc IML from SAS® studio was used to generate coefficients for polynomial contrasts. Means were considered significantly different when the P-value is less than 5% and tendencies was similar to the study of Freiria et al (2018) on kinetic parameters of in vitro ruminal degradation with combinations of exogenous enzymes in ruminant diets. In our study, the highest level of both enzymatic complexes leads to highest RS release but as per Mao et al (2013) the middle enzymes doses were more effective.…”