Title : Biofortification of zinc and manipulation of its overall quantity in mealworm (Tenebrio molitor) larvae by using zinc-enriched substrate
Abstract:
Current estimates predict that the human population might surpass 9 billion individuals by 2050 which presents the challenge of providing nutrition and battling malnutrition despite growing demands. According to the FAO, malnutrition in the form of zinc-deficiency affects about 30 percent of the world’s population. In recent years, insects are being (re-)introduced worldwide as an alternative protein source to conventional livestock production. The yellow mealworm (Tenebrio molitor L.) is one of the most widespread species that are commercially produced; mainly on mixed-grain diets. Insects have been shown to accumulate heavy metals and micronutrients, making the yellow mealworm a promising candidate for zinc supplementation in human diets. Rearing the larvae in zinc-enriched substrate raised their overall zinc content to up to three times the control level. However, in-vitro gastrointestinal digestion of our test larvae shows that the bioaccessibility of zinc after drying of the larvae can be as low as 20-40%, depending on the drying process. One reason for the low amount of resorbable zinc might be phytic acid which has been shown to diminish zinc bioaccessbility in certain animals and is a major component in mixed-grain diets. Our research investigates the impact of a modified substrate composition on the quantity of bioaccessible zinc in mealworm larvae. The possibility to increase the larvae’s zinc content and improve overall bioaccessibility of micronutrients by altering the substrate composition has the potential to combat zinc deficiency in humans and thus is a promising field of study where more research is needed.
