Impact of ergot-contaminated feed on yellow mealworm larvae performance and diet preference

Abstract

This study aimed to determine if ergot alkaloids (EA) would accumulate in yellow mealworm larvae (YML, Tenebrio molitor) when present in their diets and investigate effects on production and survival. Larvae were reared on one of four diets: a control, low, medium, and high containing 63, 3,863, 8,471 and 15,316 μg/kg total EA, respectively. Each diet had five replicates with 150 YML per replicate totalling 3,000 for the 21-day trial. Initial and final weights of the feed and larvae were collected. Ergot alkaloid concentrations in YML at d 21 were 32.6, 94.0 and 155.5 μg/kg in the low, medium, and high treatments respectively, with none detected in those fed the control diet. The frass from YML fed the control, low, medium and high diets contained 18, 364, 1,094, and 1,424 μg/kg total EA, respectively. Feed intake was reduced in larvae fed the low, medium and high treatments relative to the control at 23.3-24.9 g/21 d compared to 30.1 g in the control (P=0.02). Feed-to-gain ratios, average daily gain, and final body weights did not differ among treatments (P>0.05). The larvae did not display any preference for diets when allowed to choose between the four diets (P>0.05). Larvae accumulated only low levels of EA from their diets and although feed intake was depressed, growth was maintained. Further research is required to determine the safety of yellow mealworm reared on EA-contaminated diets.

Farmed Yellow Mealworm (Tenebrio molitor; Coleoptera: Tenebrionidae) Welfare: Species-Specific Recommendations for a Global Industry

“…mycotoxins such as DON, ZEN, Diacetoxyscirpenol (DAS), fumonisin B1, and HT-2/T-2 toxins did not appear to affect survival in YML (Tables 1 and 2; but see Guo et al 2014). Aflatoxin B1 (AFB1) produced by Aspergillus spp., and EAs produced by Claviceps spp., also did not affect survival (Bosch et al 2017;Ochoa-Sanabria et al 2022;Zhao et al 2022). Davis et al (1975) (Davis and Smith, 1977).…”

“…Behavioral avoidance of contaminated substrates has been recorded with other mycotoxins: YML reduced their intake of EA-contaminated feed over 21 days, despite no apparent preference/avoidance of contaminated feed after 20 minutes of exposure (Ochoa-Sanabria et al 2022). Avoidance behavior strongly correlated with toxin-induced mortality (Guo et al 2014).…”

“…The IAFF industry is interested in the reclamation of mycotoxincontaminated grains as feed for YML. Mycotoxin bioaccumulation, and/or the transformation of toxins into more dangerous compounds, can occur in YML (often at low levels; Niermans et al 2019;Ochoa-Sanabria et al 2022), representing a potential food/feed safety concern when rearing YML on contaminated substrates (Bordiean et al 2020; but see Duhra et al 2021; van Broekhoven et al 2017).…”