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

Aaron Beattie,Barry Blakley,Natacha Hogan,Martin Reaney,Kayla Madder,Fiona Buchanan,Cedric Gillott,Carlos Ochoa Sanabria

doi:10.3390/toxins11050282

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.

Highlights

Fusarium mycotoxins in food and feed are a recurring problem for crop and animal production worldwide
In years with high Fusarium infection, farmers are challenged to sell their grain if the level of DON in animal feed would exceed the regulatory limit 1000–5000 μg/kg established by the Canadian Food Inspection Agency (CFIA) [4]
Van Broekhoven et al [11] reported no effect on survival when yellow mealworm larvae consumed concentrations of DON from either a DON-spiked (8000 μg/kg), or a natural Fusarium-infected wheat sources (4900 μg/kg DON); DON was excreted in frass at a proportion of 41% and 14%, respectively. These findings suggest that yellow mealworm larvae may detoxify or biotransform DON into derivative forms or unknown metabolites

Summary

Introduction

Fusarium mycotoxins in food and feed are a recurring problem for crop and animal production worldwide. Known as mycotoxins, which can downgrade the nutritive, physical, and chemical qualities of grain due to the presence of Fusarium-damaged kernels (FDK) [2]. In 2014, it was estimated that two million metric tonnes of wheat and durum were downgraded to salvage (greater than 10% FDK) costing 600 million dollars to Canada’s economy. Approximately one billion dollars in losses were associated with widespread Fusarium infection in Western Canadian wheat crops [3]. In years with high Fusarium infection, farmers are challenged to sell their grain if the level of DON in animal feed would exceed the regulatory limit 1000–5000 μg/kg established by the Canadian Food Inspection Agency (CFIA) [4]. Grain with significant amounts of FDK is either blended with uncontaminated or low FDK grain, or condemned to salvage grain with no commercial value

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