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.