Synthesis of selenium conjugated insects’ protein in Hermetia illucens larvae as poultry feed

Abstract

Selenium (Se) is an essential trace element for human health and livestock growth. The element can be fed in inorganic or organic forms, depending on the diet’s chemical makeup and how it influences the accumulated amount of Se in the tissues of animals. Insects are known to be natural bio-accumulators of various nutrients, but research on the capacity of insects to be bio-enriched with Se in feed is still limited. The aims of this study were to synthesise Se conjugated insects’ protein and examine how effectively they can deliver selenium to black soldier fly (BSF, Hermetia illucens) larvae. In this study, BSF larvae were reared on different substrates with four levels of dietary sodium selenite supplementation (0, 100, 200 and 400 mg/kg). BSF larvae were analysed for biomass yield, nutritional value, and Se content. We revealed that selenium content in the fortified BSF larvae was several orders of magnitude higher than in the unfortified ones. There were significant differences between doses of selenium delivered to BSF larvae by different selenium compounds. Inductively coupled plasma mass spectrometry (ICP-MS) analysis of these BSF larvae has shown that there was a higher accumulation of total selenium content in the treated samples (348 mg Se/g DW) as compared to control (0.64 mg Se/g DW). Se conjugated insects’ protein can withstand as high as 400 mg sodium selenite without compromising its growth pattern and BSF larvae biomass yield and nutritional value. Collectively, the current study proposes that, Se conjugate BSF larvae with high organic Se content and can serve as selenium feed additives.