Diet Induced Modifications of Fatty-Acid Composition in Mealworm Larvae (Tenebrio molitor)

The diet of Western human societies is characterized by an excess of saturated fatty acids (FAs) and a high concentration of ω-6 relative to ω-3 polyunsaturated FA (PUFA). These unbalanced diets are suspected to trigger diseases and disorders. To alleviate this public health concern, the production of healthier meat with more PUFAs of higher ω-3 concentration could potentially be achieved by modifying livestock diets. The high nutritional value and limited breeding costs of edible insects have brought insect feed into the discussion as a promising fat source for animal and human diets. In this study, we sought to increase the amount of ω-3 PUFAs in mealworm (Tenebrio molitor) larvae. We investigated the effects of diets varying in ω-3/ω-6 ratio and FA concentration but similar in PUFA proportion on larva FA composition. Mealworm larvae showed significant plasticity in lipid composition. High dietary ω-3/ω-6 ratios induced an increase in the proportion of ω-3 and a decrease in ω-6, which resulted in higher larval ω-3/ω-6 ratios, but also in higher larval PUFA proportion. Increasing FA concentrations in larva diets also favored the accumulation of PUFAs to the detriment of monounsaturated and saturated FAs. Providing ω-3-rich seeds to mealworm larvae could allow the production of economical animal fat with healthier PUFA percentages (> 60%) and ω-3/ω-6 ratios (>0.5).