Inclusion of the microbial additive Vitafert in the in vitro ruminal fermentation of a goat diet

Resumen

For determining the effect of Vitafert on the kinetics and fermentation indicators of a goat diet (80:20 forage: concentrate ratio), the in vitro gas production technique was applied. One gram of the diet was incubated alone (0 level) or with three Vitafert levels (110 ?L, 150 ?L and 210 ?L), equivalent to 4.5, 6.0 and 8.5 mL Vitafert kg-1. For each treatment specific blanks were established. Gas production was measured until 120 h and its kinetics was estimated by the Gompertz model. At 120 h, DM and NFD degradability were determined. Production and efficiency of the microbial biomass synthesis were calculated. A completely randomized design was used. MANOVA did not show treatment x hours of incubation interaction regarding gas production. On applying a linear model, there were no differences in accumulated gas production, although the specific blanks showed increase in gas production, as the Vitafert level increased. Differences between timings were only at two hours of incubation as regard the remaining hours (P < 0.001), Vitafert inclusion did not influence on the kinetic parameters. The time at which the maximum speed was attained ranged between 20 and 21 h. The 4.5 level increased DM and NFD degradability (P < 0.05), and the 8.5 level increased the production and efficiency of microbial biomass synthesis (P < 0.01). It is concluded that Vitafert did not affect gas production or the kinetic parameters of the diet fermentation. The 4.5 level increased DM and NFD degradability and the 8.5 level, the production and efficiency of the microbial biomass synthesis.
Key words: Vitafert, goats, gas production, kinetic parameters, microbial biomass