Isolation of rumen cellulolytic bacterial consortia and their in vitro simulation of rumen microbiota manipulation

Abstract

Introduction. Isolation and manipulation of rumen cellulolytic bacterial consortia (CBC) improve fiber degradation under in vitro conditions. Objective. To obtain CBC from different substrates and to simulate the manipulation of ruminal microbiota (RM) by means of an in vitro gas production test. Objective. Obtain CBC from different substrates and simulate the manipulation of ruminal microbiota (RM) by in vitro gas production test. Materials and methods. The experiment was conducted from January to June 2024 at the Autonomous University of Guerrero, Cuajinicuilapa, Guerrero, Mexico. CBC were obtained from rumen fluid in selective culture media using ground sawdust (CBCa), Mulatto grass stalk (CBCt) and ground Mulatto grass (CBCm) as substrate. Two in vitro assays were performed: a) Evaluation of obtained CBCs and, b) Addition of CBCs to MR. In both, partial biogas production was measured from 0 to 24 h, 24 to 48 h and 48 to 72 h, as well as cumulative production. Dry matter degradation (DMD) and cellulolytic enzyme activity (CEA) were measured at 24, 48 and 72 h. The variables were analyzed in a design based on the design of the CBCs. The variables were analyzed in a completely randomized design. Results. In trial 1, CBCa produced higher cumulative biogas (p<0.05); DMD at 24 and 72 h was higher for CBCa (p<0.05); DMD at 48 h and AEC showed no difference between CBCs (p>0.05). In trial 2 they showed that the addition of CBCs to the RM did not modify the partial biogas production, the DMS at 24, 48 and 72 h, nor the CEA at 24 and 48 h (p>0.05); but the addition of CBCm increased 13.8 and 36.3 % the cumulative biogas production and CEA at 72 h. Conclusion. The CBCs obtained from the mulatto grass allow manipulation of the RM after in vitro simulation under the specific conditions of the present study.