Efecto de un extracto de regaliz rico en flavonoides sobre la actividad protozoaria y la fermentación ruminal in vitro

Resumen

Different doses (0.25, 0.5, 1 and 2 mg/ml) of a liquorice extract rich in flavonoids were incubated in vitro in diluted cow’s rumen fluid with [14C] radioactive-labelled bacteria to study the effect on bacteria predation by protozoa. Additionally, 24 h in vitro incubations with this extract at 0.5, 1 and 2 mg/ml in diluted rumen fluid were carried out to determine the effect on fermentation and protozoa motility. Incubations of liquorice extract added at 0.5 mg/ml resulted in a reduction (P<0.001) of bacterial predation by protozoa, in comparison with the control. This effect was stronger (P<0.001) at 1 and 2 mg/ml, causing the complete abolition of protozoa. In vitro 24 h incubations with 1 and 2 mg/ml of liquorice extract resulted in a decrease of acetic/propionic ratio and ammonia concentrations (P<0.001 and P=0.01, respectively). Also, protozoa motility over time was reduced (P<0.001) when the highest concentration of the extract was incubated. These results showed the potential of a liquorice extract rich in flavonoids as a antiprotozoal agent causing a shift in rumen fermentation towards propionate and decreasing ammonia concentration. Therefore, the addition of a liquorice extract rich in flavonoids could potentially improve the efficiency of the feed utilization by ruminants.