Biogenic amines in silage. 3. The occurrence of six biogenic amines in farm-scale grass and maize silages.

Concentrations of putrescine (PUT), cadaverine (CAD), spermidine (SPD), spermine (SPM), histamine (HIS) and tyramine (TYR) in 53 grass silages and 54 maize silages were determined using an HPLC method. Concentrations of all amines excluding SPD in grass silages decreased significantly with increasing dry matter (DM) contents and decreasing acetic acid concentrations. The mean concentrations were 1310, 642, 414, 139, 120 and 33.6 mg/kg for TYR, CAD, PUT, SPM, HIS and SPD respectively in grass silages of 20-30% DM. The maximal values found were twice to five times higher than the mean values. The effect of increasing DM on the amines concentrations was not evident in maize silages. The mean concentrations, regardless of the DM content, were surprisingly high: 435, 388, 341, 71.7, 25.1 and 5.4 mg/kg for TYR, PUT, CAD, HIS, SPD and SPM. The maximal values in maize silages were three times to ten times higher than the mean values. Considering that maize silage forms the great proportion of the diets of cattle during long-term winter feeding, further toxicological and physiological research should be carried out.