The prevalence of mycotoxins and their relation to nutrient composition of maize and grass silage

In this study, samples of maize and grass silage were collected from various farms of Lithuania and were analysed for mycotoxins: aflatoxin B1 (AFB1), deoxynivalenol (DON), T-2 toxin (T-2) and zearalenone (ZEA), over the 2017-2019 period. Silage nutrient composition, including content of dry matter, crude protein, crude fibre, starch (for maize), and acidity (pH) were investigated, and fermentation degree was computed. All samples contained at least one mycotoxin, 85% of samples were co-contaminated with all four mycotoxins tested, 13% of samples contained three and only 1.5% of samples contained two mycotoxins. In general, the concentrations of DON, ZEA and T-2 were respectively 5, 1.7 and 2 times higher in maize silage than in grass one. Maize silage had the highest levels of ZEA and AFB1, exceeding the European Union's (EU) maximum allowable limits. In grass silage, mycotoxin with the highest concentration exceeding the allowable limits was AFB1. Between the experimental years, statistically significant differences were found only in T-2 content in maize silage. Silage storage had an impact only on AFB1 concentrations: its highest concentration (10.9 +/- 1.1 mu g kg(-1)) was found in trench silos, while in silage clamps and bales that ones were lower by 48% and 44%, respectively. DON negatively correlated with dry matter in grass silage. ZEA negatively correlated with crude protein content and pH in maize silage and with dry matter and crude fibre content and pH in grass silage, but positively correlated with fermentation degree in both silages. T-2 negatively correlated with crude protein content and positively correlated with crude fibre content in grass silage.