This study aimed to determine the effects of different roughages in TMR inoculated with or without coculture of L. acidophilus and B. subtilis on in vitro rumen fermentation and microbial population.
Three TMRs formulations composed of different forages were used and each TMR was grouped into two treatments: non-fermented TMR and fermented TMR (FTMR) (inoculated with coculture of L. acidophilus and B. subtilis). After fermentation, the fermentation, chemical and microbial profile of the TMRs were determined. The treatments were used for in vitro rumen fermentation to determine total gas production, pH, ammonia-nitrogen (NH3-N), and volatile fatty acids (VFA). Microbial populations were determined by quantitative real-time PCR. All data were analyzed as a 3×2 factorial arrangement design using the MIXED procedure of Statistical Analysis Systems.
Changes in the fermentation (pH, lactate, acetate, propionate, and NH3-N) and chemical composition (moisture, CP, CF, and ash) were observed. For in vitro rumen fermentation, lower rumen pH, higher acetate, propionate, and total VFA content were observed in the FTMR group after 24 h incubation (p<0.05). FTMR group had higher acetate concentration compared with the non-fermented group. Total VFA was highest (p<0.05) in TMR containing Italian ryegrass and corn silage (F-CF and F-IRS-CS) than that of TMR diet containing oat, timothy, and alfalfa hay. The microbial population was not affected by the different TMR diets.
The use of Italian ryegrass silage and corn silage, as well as the inoculation of coculture of L. acidophilus and B. subtilis, in the TMR caused changes in the pH, lactate and acetate concentrations, and chemical composition of experimental diets. In addition, fermented TMR composed with Italian ryegrass silage and corn silage altered ruminal pH and VFA concentrations during in vitro rumen fermentation experiment.