Pre-incubation of ruminal inocula to assess in vitro gas production and digestibility

WAWRZKIEWICZ, M.; CANTET, J. M.; JAURENA, G.; COLOMBATTO, D.

CIêNCIA RURAL

UNIV FEDERAL SANTA MARIA

Año: 2020 vol. 50

0103-8478

In vitro gas production techniques represent a valuable tool to describe the kinetics of ruminal degradation of food. However,the ruminal liquor used as a microbial inoculum has been a great source of variation and error. A standardization of this factor shouldcontribute to assure the independence of food fermentation parameters from those of the inocula. In this research it was hypothesized that acontrolled pre-incubation treatment of ruminal liquor could contribute to stabilize and homogenize the undigested residues of blanks and as aconsequence, of the production of residual cumulative gas production (CGP). A pre-incubation (i.e. previous real incubation) of rumen inoculawas developed with a simple substrate similar to the diet offered to donors at 1% w/v for 0, 1, 2 and 4 h (Control, Prei-1, Prei-2 and Prei-4treatments respectively). Once the pre-incubation hours were completed, they were incubated with contrasting substrates and without substrate(i.e. blanks) in order to evaluate the CGP, in vitro digestibility of the DM and fermentation products. Although, the fermentative activity of thepre-incubated inoculums worked satisfactorily in the in vitro system, contrary to what was speculated, residues of the pre-incubation increasedthe variability and heterogeneity of variances among blanks. Consequently, it was concluded that the pre-incubations did not work to generatemore homogeneous and less variable ruminal liquor for the in vitro gas production system