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

Abstract

Within the European Union (EU), edible insects need to be approved as “Novel Food” according to Regulation (EU) 2015/2283 and must comply with the requirements of European food law with regard to microbiological and chemical food safety. Substrates used for feeding insects are susceptible to the growth of Fusarium spp. and consequently to contamination with trichothecene mycotoxins. Therefore, the current study aimed to investigate the influence of T-2 and HT-2 toxins on the larval life cycle of yellow mealworm (Tenebrio molitor (L.)) and to study the transfer of T-2, HT-2, T-2 triol and T-2 tetraol in the larvae. In a 4-week feeding study, T. molitor larvae were kept either on naturally (oat flakes moulded with Fusarium sporotrichioides) or artificially contaminated oat flakes, each at two levels (approximately 100 and 250 μg/kg total T-2 and HT-2). Weight gain and survival rates were monitored, and mycotoxins in the feeding substrates, larvae and residues were determined using LC-MS/MS. Larval development varied between the diets and was 44% higher for larvae fed artificially contaminated diets. However, the artificially contaminated diets had a 16% lower survival rate. No trichothecenes were detected in the surviving larvae after harvest, but T-2 and HT-2 were found both in the dead larvae and in the residues of naturally and artificially contaminated diets.

A systematic literature review on the effects of mycotoxin exposure on insects and on mycotoxin accumulation and biotransformation

“…The study of Piacenza et al ( 2020 ) showed that no T-2, HT-2, T-2 triol, or T-2 tetraol were detected (in levels above the LOD) in the surviving larvae or in the dead larvae collected from the control diets. However, after examination of the dead larvae collected from the other diets, 44.2 μg/kg T-2 was found in the body of the larvae fed with the naturally contaminated diet (250 μg/kg total T-2 and HT-2) and 7.7 μg/kg T-2 in the larvae fed the naturally contaminated diet (100 μg/kg total T-2 and HT-2) and the artificially contaminated diets.…”

“…250 μg/kg T-2/HT-2 toxins gained 44% more weight than the control group fed a natural diet. Additionally, larval weight gain was significantly higher when fed with an artificially contaminated diet than when fed with naturally contaminated diets (Piacenza et al 2020 ). In general, most studies focused on the effect of mycotoxin exposure on weight gain in T. molitor larvae.…”

“…Larvae fed with either an artificially contaminated diet or a naturally contaminated diet containing approximately 100 and 250 μg/kg total T-2 / HT-2 for 4 weeks resulted in an average mortality of 11% in T. molitor larvae considering all diets. Interestingly, when fed the artificially contaminated diet, 16% higher mortality was observed as compared to the naturally contaminated diet, and this effect seemed to be independent of the concentration (Piacenza et al 2020 ). Camenzuli et al ( 2018 ) exposed A. diaperinus larvae to 17 different treatments, including single spiked concentrations of AFB 1 (8–390 µg/kg), DON (3900–112,000 µg/kg), ZEN (280–13,000 µg/kg), OTA (170–1700 µg/kg) and combined spiked mycotoxin concentrations of up to 100,000 µg/kg and found no significantly different mortality in these treatment groups as compared to the control group (Camenzuli et al 2018 ).…”

“…The percentage of excreted T-2 found in the residual materials was higher when fed a naturally contaminated diet (51.7–66.5%) as opposed to an artificially contaminated diet (36.5–55.1%). HT-2 was only observed in the residual feed material of the larvae fed the artificially contaminated diets; interestingly, it seemed that the concentration found was not affected by the initial dose (Piacenza et al 2020 ). Currently, no data are available on the accumulation or reduction of OTA in T. molitor residues.…”

Insects and Public Health: An Overview

“…In particular, insects have a fundamental role as pollinators. Wild and managed pollinators are closely linked to human well-being through their pivotal role in wild plant reproduction and crop production, affecting the yield of approximately 75% of the world’s most important crop types [ 3 ]; therefore, we can state that insect pollinators are responsible for one of every three bites of food we eat [ 4 ]. In addition, insects, considered as a food (re)source, appear more sustainable when compared with other sources of animal protein, thus possibly contributing to alleviating the pressure on the environment and the planet in feeding a densely populated world [ 5 ].…”