Bioconversion of Deoxynivalenol by Mealworm (Tenebrio molitor) Larvae: Implications for Feed Safety and Nutritional Value

Abstract

Deoxynivalenol (DON) is one of the most common trichothecene mycotoxins found in cereals, posing a significant hazard to food and feed safety. Insects, especially the yellow mealworm (Tenebrio molitor), offer promising alternative protein sources; however, their capacity to metabolise mycotoxins and the nutritional implications are still not fully understood. In this study, T. molitor larvae were reared for two weeks on diets containing DON at 663 or 913 µg/kg, and their biomass was analysed using Liquid Chromatography–Quadrupole Time-of-Flight Mass Spectrometry (LC-QTOF) for DON metabolites and free amino acids, as well as Gas Chromatography–Flame Ionization Detector (GC-FID) for fatty acid profiles. Larvae metabolised DON via multiple pathways, including sulfonation, glucuronidation, sulfation, glucosylation, and de-epoxidation, with a time- and dose-dependent shift towards glucosylation and de-epoxidation. DON exposure significantly reduced the levels of essential amino acids such as methionine, lysine, phenylalanine, and isoleucine, and lowered metabolic intermediates like aspartic and glutamic acid. Conversely, prolonged DON exposure increased linoleic acid levels in larval fat, indicating altered lipid metabolism. These findings demonstrate that T. molitor larvae detoxify DON but incur measurable metabolic costs, leading to changes in amino acid and fatty acid profiles. The dual effect—reduction of toxin levels and nutritional shifts—highlights both the potential and the challenges of using insects for sustainable feed production.