Changes in saponin content and composition during the ensilage of alfalfa (Medicago sativa L.)

Two varieties of alfalfa (Medicago sativa L.) were ensiled under laboratory conditions after being treated with formic acid or after wilting for different times. Intact saponins, using an HPLC method, were determined in the starting material and after ensiling. The presence of two saponins were detected and measured in the experiment using the variety Hodonيnka and three saponins in the second experiment using the variety Pلlava. Soyasaponin I was present in both varieties, whilst the two other saponins, designated as saponin A and saponin B, had chromatographic properties consistent with glycosides, of medicagenic acid. Significant decreases in saponin concentrations were observed after ensiling varying from 12% to 100%. Soyasaponin I was found to be relatively stable, while saponin A was not detected after the first week of ensiling. Treatment with formic acid stabilised saponin B and soyasaponin I for the variety Pلlava in contrast to the other treatments.