60 Occurrence of Mycotoxins in 2019 US Corn-based Feed Ingredients

Abstract Mycotoxins are secondary fungal metabolites that are detrimental to animal health and productivity. This study investigated occurrence and contamination levels of mycotoxins in the 2019 US corn harvest, including corn grain and corn byproduct feed ingredients (distillers dried grains, gluten feed, etc.). Corn samples from the 2019 harvest and corn DDGS and other byproducts from October 2019 through April 2020 were screened via the LC-MS/MS technique for the presence of six major mycotoxin groups: aflatoxins, type A trichothecenes, type B trichothecenes (B-Trich), fumonisins (FUM), zearalenone (ZEN) and ochratoxin A. Parameters of the main toxins found were compared to the two prior harvest years using the Kruskal-Wallis Test (Prism7, GraphPad, La Jolla, CA) and are presented in Table 1. Mean toxin count per sample in corn grain was similar in 2019 as 2018, with just over two toxins per sample. Mean B-Trich level (parts per billion, ppb) was elevated in 2019 from 2017. Fumonisin contamination increased in 2019 compared to 2017, and prevalence was similar to 2018. Zearalenone contamination and prevalence were similar in 2019 compared to 2018 levels. Co-contamination in corn byproduct feeds was steady, averaging nearly three toxins per sample. Mean B-Trich contamination was higher than the 2017 crop, and FUM contamination was higher in 2019 than 2017 and 2018. Zearalenone levels in 2019 byproducts are the highest seen in the past three years. Preliminary results of the 2019 corn-based feed ingredients survey suggest mycotoxin occurrence and contamination levels are approaching those observed in the challenging 2018 crop. Furthermore, there are continued concerns for co-contamination and greater ZEN contamination that may impose negative effects on growth, health and reproductive performance in ruminants.