359 Occurrence of mycotoxins in 2018 us corn-based feed ingredients

Abstract Mycotoxins are harmful secondary fungal metabolites that are detrimental to animal health and productivity. This study investigated occurrence and contamination levels of mycotoxins in the 2018 US corn harvest including corn grain, corn silage and corn by-product feed ingredients (distillers dried grains, gluten feed, etc.). Corn and corn silage samples marked as 2018 harvest from feed mills, livestock producers, and integrators and corn DDGS and other by-products from mid-August 2018 through January 2019 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. 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 increased in 2018 versus 2017, returning to over two toxins per sample as in 2016. Mean B-Trich level (ppb) is elevated in 2018 from 2017. Although ZEN contamination does not differ from prior years, prevalence increased to 45% from 25% in 2017. Co-contamination in corn by-product feeds is steady, averaging nearly three toxins per sample. Mean B-Trich is higher than the 2017 crop, while FUM contamination is similar to 2017. ZEN levels in 2018 by-products are the highest seen in the past three years. Corn silage has increased in mean toxin count per sample and contamination levels of B-Trich and ZEN in 2018 versus 2017. Prevalence of B-trich has remained constant from year to year, while both ZEN and FUM prevalence have increased from 2017 to 2018. Preliminary results of the 2018 corn-based feed ingredients survey suggest mycotoxin occurrence and contamination levels are approaching those observed in the challenging 2016 crop with continued concerns for co-contamination.