Yellow Mealworm Larvae (Tenebrio molitor) Fed Mycotoxin-Contaminated Wheat—A Possible Safe, Sustainable Protein Source for Animal Feed?

Abstract

The aim of this study was to determine the potential for accumulation of deoxynivalenol (DON) in yellow mealworm larvae (Tenebrio molitor) reared on high DON Fusarium-infected wheat and investigate the effects on production, survival and nutritional traits. Wheat containing 200 μg/kg DON was used as the control diet. A different source of wheat was sorted into six fractions and mixed to obtain low (2000 μg/kg), medium (10,000 μg/kg) and high (12,000 μg/kg) levels of DON. Each diet was replicated five times with 300 or 200 mealworms per replicate for the feeding and breeding trials, respectively. Trial termination occurred when the first two pupae were observed (32–34 days). There was no difference in the concentrations of DON detected in the larvae between diets that ranged from 122 ± 19.3 to 136 ± 40.5 μg/kg (p = 0.88). Excretion of DON was 131, 324, 230 and 742 μg/kg for control, low, medium and high, respectively. Nutritional analysis of larvae showed maximum crude protein of 52% and crude fat of 36%. Ash, fiber, chitin, fatty-acids and amino-acid content were consistent across diets. Survival was greater than 96% for all life stages and average daily gain ranged from 1.9 ± 0.1 to 2.1 ± 0.1 mg/day per mealworm. Larvae accumulated low levels of DON from Fusarium-infected wheat diets suggesting contaminated wheat could be used to produce a sustainable, safe protein source.

Distribution of T-2 toxin and HT-2 toxin during experimental feeding of yellow mealworm (Tenebrio molitor)

“…Recent studies have shown that insects — if kept on rotten and/or mouldy substrates—may render hazardous metabolites harmless via their own metabolism or largely excrete them, especially mycotoxins, such as zearalenone or type B trichothecenes (Niermans et al 2019 ; Ochoa Sanabria et al 2019 ; Van Broekhoven et al 2017 ). However, as shown for zearalenone, metabolism in T. molitor may also result in the formation of compounds of higher toxicity, such as α-zearalenol (Niermans et al 2019 ).…”

SPME‐GC/MS Analysis of Volatile Compounds Contained in the Insect Larvae of Tenebrio molitor and Leptinotarsa decemlineata before and after Using Insecticides

“…It naturally occurs under the decaying bark of deciduous trees, as well as in tree hollows. It is a species which is bred as food for arthropods and cold‐blooded vertebrates . As a harmful species, it feeds in warehouses where flour, bran, rusks and other cereal products are stored.…”

Prospects of insects as food and feed

“…The black soldier fly has shown to be able to degrade pathogens (Erickson et al 2004), mycotoxins (Purschke et al 2017), insecticides (Purschke et al 2017), and fungicides (Lalander et al 2016). Also, the yellow mealworm, when wheat was contaminated with the mycotoxin deoxynivalenol, accumulated only very low levels of the mycotoxin, suggesting that it can still be used to produce a sustainable, safe protein source (Sanabria et al 2019).…”