Effects of Selenite and Selenate on the Growth, Nutrient Composition, Selenium Species, and In Vitro Digestibility of Mealworm Tenebrio molitor
by
, ,
Shizhong Yue
1,2,3,*
,
Shan Jiang
4,
Shuwen Zhang
5,
Chengjie Wang
5,
Wenqi Zhang
5,
Tianran Li
5,
Ruiping Wang
1,2,3,
Huaitao Li
6,
Xingtang Zhao
2,3,5
,
Huaishen Li
6 and
Jiafeng Yu
2,3 1
Institute of Biophysics, Dezhou University, Dezhou 253023, China
2
International Joint Laboratory of Agricultural Food Science and Technology of Universities of Shandong, Dezhou University, Dezhou 253023, China
3
Shandong Engineering Research Center of Green and Efficient Breeding and Food Deep Processing of Featured Livestock and Poultry, Dezhou University, Dezhou 253023, China
4
College of Life Sciences, Dezhou University, Dezhou 253023, China
5
Belgorod Institute of Food Science, Dezhou University, Dezhou 253023, China
6
Zibo Jinyuan Biotechnology Co., Ltd., Zibo 256414, China
*
Author to whom correspondence should be addressed.
Insects 2026, 17(2), 177; https://doi.org/10.3390/insects17020177
Submission received: 11 January 2026
/
Revised: 31 January 2026
/
Accepted: 4 February 2026
/
Published: 6 February 2026
(This article belongs to the Special Issue Insects as Food: Advances in Edible Insect Research and Applications)
Simple Summary
The yellow mealworm is frequently regarded as a promising, sustainable, high-quality protein-containing foodstuff that can be consumed by humans. Selenium has been demonstrated to be an essential micronutrient for humans and animals, as it plays a crucial role in promoting physical health. Nevertheless, it is important to note that inorganic selenium is toxic to organisms at elevated concentrations. Furthermore, there is a paucity of information regarding the changes in nutritional components, selenium enrichment, and the biotransformation efficiency of the worms. The present study employed two types of inorganic selenium (selenite and selenate) to address the aforementioned issues, with the purpose of selenium-enriched mealworm cultivation and utilisation. Inhibited larval biomass was observed in the presence of elevated concentrations of inorganic selenium, with both Se forms stimulating crude protein and polysaccharide synthesis. A dose-dependent Se accumulation pattern and limited bioaccumulation capacity were identified in mealworms. However, a remarkable capacity for Se biotransformation was also observed, yielding a higher proportion of organic Se in mealworms, and selenocystine was identified as the predominant compound. The in vitro gastrointestinal digestion test demonstrated a high bioaccessibility of mealworm-derived Se.
Abstract
This study systematically compared the growth performance, nutrient composition, accumulation and speciation of selenium (Se), and in vitro bioaccessibility in yellow mealworm (Tenebrio molitor L.) larvae, which were reared on substrates supplemented with selenite (Se4+) and selenate (Se6+) at concentrations of 0, 5, 10, and 20 mg/kg over 28 days. The results showed that high Se concentrations (≥10 mg/kg) significantly reduced larval biomass, with Se6+ having a slightly stronger inhibitory effect than Se4+. The mealworms effectively accumulated Se in a dose- and form-dependent manner. Peak total Se concentrations were observed on day 14, after which there was a decline, suggesting the presence of potential elimination mechanisms, such as moulting. The bioaccumulation factors (BAFs) were all below 1, indicating its limited enrichment capacity for both Se4+ and Se6+. Nutrient composition was altered, with both Se forms stimulating crude protein and polysaccharide synthesis while inhibiting fat accumulation. Mineral content (Mg, Fe, Zn) was also modulated, with differences observed between the Se4+ and Se6+ treatments. Notably, mealworms exhibited a remarkable ability to biotransform inorganic Se into organic forms, with organic Se proportions exceeding 79% in all treatments. Selenate was more efficiently bio-converted, yielding a higher proportion of organic Se. In vitro gastrointestinal digestion revealed significantly higher Se bioaccessibility from Se6+-treated mealworms (up to 85.12%) than from Se4+-treated ones (up to 60.67%). Analysis of the bioaccessible fraction by Se speciation identified SeCys2 as the dominant compound (>92% of the detected species), with much lower levels of SeMet. Trace amounts of unmetabolised Se6+ were only detected in the Se6+-exposed groups. These findings highlight T. molitor as an efficient bioreactor for producing bioaccessible, organically bound Se, primarily as SeCys2, with Se6+ being the more favourable precursor for generating a high-quality, bioavailable source of Se for potential use in feed or food.
